nuclei (nu:´kli: ai', nyu:´-) •n. pl. of NUCLEUS

nucleic acid (nu: kli:´ik, nyu:-; often, -klei´-) any of a group of essential complex organic acids found in all living cells: the two types are DNA and RNA and consist of long chains of nucleotide units with each unit composed of phosphoric acid, a carbohydrate, and a base derived from purine or pyrimidine

nuclein (nu:´kli: in, nyu:´-) •n. any of a group of decomposition substances found in the nuclei of cells that are intermediate to nucleoproteins and nucleic acids [NUCLE(US) + -IN¹]

nucleo- (nu:´kli: ou´, nyu:´-; -э) combining form 1 nucleus {nucleophile} 2 nuclear {nucleoplasm} 3 nucleic acid {nuclease, nucleoprotein} Also, before a vowel, nu´cle-

nucleolus (nu: kli:´э lэs, nyu:-) pl. -li' (-lai') a conspicuous, usually spherical, dense body in the nucleus of most cells, consisting of protein and RNA: ribosomes are produced here: see CELL, illus. Also nu´cle·ole' •n. nu·cle´o·lar •adj. [ModL < LL, dim. of L nucleus]

nucleon (nu:´kli: än', nyu:´-) •n. any of a class of baryons that are the fundamental particles making up the atomic nucleus, consisting of the neutron and the proton nu'cle·on´ic •adj. [NUCLE(US) + (PROT)ON]

nucleonics (nu:'kli: än´iks, nyu:'-) •n.pl. [with sing. v.] the branch of physics dealing with nucleons or with nuclear phenomena and esp. with practical applications of nuclear physics [prec. + -ICS]

nucleophile (nu:´kli: э fail', nyu:´-) •n. an atom or molecule that has an affinity for atomic nuclei or that donates electrons to form a covalent bond nu'cle·o·phil´ic (-fil´ik) •adj. [NUCLEO- + -PHILE]

nucleoplasm (-plæz'эm) •n. the protoplasm that composes the nucleus of a cell nu'cle·o·plas´mic •adj. [NUCLEO- + -PLASM]

nucleoprotein (nu:'kli: ou prou´ti:n, nyu:'-; -prout´i: in) •n. any of a class of compound proteins consisting of nucleic acid linked to protein, found in the nuclei and surrounding cytoplasm of living cells [NUCLEO- + PROTEIN]

nucleoside (nu:´kli: ou said', nyu:´-) •n. any of various compounds consisting of a purine or pyrimidine base linked to a carbohydrate: a major component of a nucleotide [< NUCLEO- + -OSE² + -IDE]

nucleosynthesis (nu:'kli: ou sin´θэ sis, nyu:'-) •n. the formation of heavier chemical elements from the nuclei of hydrogen or other lighter elements, as in the interior of a star [NUCLEO- + SYNTHESIS]

nucleotide (nu:´kli: ou taid', nyu:´-) •n. 1 any of several phosphate esters of nucleosides: the basic unit of nucleic acids 2 any of several compounds not found in nucleic acids, which function as coenzymes [altered < NUCLEOSIDE]

nucleus (nu:´kli: эs, nyu:´-) pl. -cle·i' (-ai') or -cle·us·es •n. 1 a thing or part forming the center around which other things or parts are grouped or collected; core 2 anything serving as a center of growth or development {the nucleus of a library} 3 Anat. a group of nerve cells in the brain or spinal column 4 Astron. the bright central part of the head of a comet 5 Biol. the central, usually spherical or oval mass of protoplasm present in most plant and animal cells, containing most of the hereditary material and necessary to such functions as growth, reproduction, etc.: see CELL, illus. 6 Bot. the central point in a starch grain 7 Chem., Physics the central part of an atom, the fundamental particles of which are the proton and neutron, except for hydrogen, which is usually composed of one proton only: it carries a positive charge and constitutes almost all of the mass of the atom 8 Organic Chem. a fundamental, stable arrangement of atoms that may occur in many compounds by atomic substitution without structural change, as the benzene ring [ModL < L, a nut, kernel, for nuculeus, dim. < nux (gen. nucis), NUT]

nuclide (nu:´klaid, nyu:´-) •n. a specific type of atom that is characterized by its nuclear properties, such as the number of neutrons and protons and the energy state of its nucleus nu·clid´ic •adj. [< prec. + -ide < Gr eidos, form: see -OID]

nude (nu:d, nyu:d) •adj. 1 completely unclothed or uncovered; naked; bare 2 Law without consideration or other legal essential: said esp. of contracts •n. 1 a nude person 2 a representation of a nude human figure in painting, sculpture, etc. 3 the condition of being nude; nakedness {in the nude} SYN. BARE¹ nude´ly •adv. nude´ness •n. [L nudus, NAKED]

nudge (nûj) nudged, nudg´ing •vt. to push or poke gently, esp. with the elbow, in order to get the attention of, hint slyly, etc. •n. a gentle push with the elbow, etc.; jog nudg´er •n. [prob. akin to Norw dial. nyggja, to push, shove, MLowG nucke, a sudden push, ult. < IE base *nue-, to jerk, shove: see INNUENDO]

nudi- (nu:´di, -dэ; nyu:´-) combining form Biol. bare, naked {nudibranch} [< L nudus, NAKED]

nudibranch (-bræŋk') •n. any of an order (Nudibranchia) of marine gastropods without a shell and with external gills nu'di·bran´chi·ate (-bræŋ´ki: it, -eit') •adj., n. [< ModL Nudibranchia: see NUDI- & BRANCHIAE]

nudie (nu:d´i:, nyu:d´i:) •n. [Slang] a cheap motion picture exploiting nudity and sex

nudism (nu:d´iz'эm, nyu:d´-) •n. the practice or cult of going nude for hygienic reasons nud´ist •n., adj.

nudity (nu:d´э ti:, nyu:d´-) •n. 1 the state, quality, or fact of being nude; nakedness 2 pl. -ties a nude figure, as in art [Fr nudité < L nuditas]

nudnik (nud´nik) •n. [Slang] a dull, tiresome, annoying person [< Yidd < Russ nudnyi, tiresome < nuda, need, boredom (< IE *neuti- > NEED) + -nik, -NIK]

Nueces (nu: ei´seis', -sэs) river in S Tex., flowing SE into the Gulf of Mexico at Corpus Christi: 315 mi. (507 km) [Sp, nuts, for the pecan trees there]

nuée ardente (nu: ei'är dänt´) pl. nuées ardentes (nu: ei'är dänt´) a thick, deadly volcanic cloud of steam, dust, ash, etc., that explodes violently, may begin to glow, and rushes down the sides of the volcano

Nuer (nu:´эr) •n. 1 pl. Nu´ers or Nu´er a member of a pastoral Nilotic people in Sudan and on the border of Ethiopia 2 their Eastern Sudanic language

Nuevo Laredo (nwei´vô lä řei´dô) city in N Mexico, on the Rio Grande, opposite Laredo, Tex.: pop. 203,000

Nuevo León (nwei´vô lei ôn´) state in NE Mexico: 25,136 sq. mi. (65,101 sq. km); pop. 2,513,000; cap. Monterrey

nugatory (nu:´gэ tör'i:, nyu:´-) •adj. 1 trifling; worthless 2 not operative; invalid [L nugatorius < pp. of nugari, to trifle < nugae, trifles]

nugget (nûg´эt) •n. a lump; esp., a lump of native gold [prob. dim. of E dial. nug, a lump]

nuisance (nu:´sэns, nyu:´-) •n. 1 an act, condition, thing, or person causing trouble, annoyance, or inconvenience 2 Law a thing or condition causing danger or annoyance either to a limited number of persons (private nuisance) or to the general public (public nuisance), or, because of its attraction, to children who will be unlikely to recognize its dangerous quality (attractive nuisance) [ME nusance < OFr < nuisir, noisir < L nocere, to annoy: see NECRO-]

nuisance tax a tax considered a nuisance because it is paid in very small amounts by the consumer

nuke (nu:k, nyu:k) •n. [Slang] 1 a nuclear weapon or submarine 2 a nuclear reactor or power plant •vt. nuked, nuk´ing [Slang] 1 to attack with nuclear weapons 2 to cook (food) in a microwave oven [< NUCLEAR]

Nukualofa (nu:'ku: э lö´fэ) capital of Tonga: pop. 28,000

null (nûl) •adj. 1 without legal force; not binding; invalid: usually in the phrase null and void 2 amounting to naught; nil 3 of no value, effect, or consequence; insignificant 4 Math. designating, of, or being zero, as: a) having all zero elements {null matrix} b) having a limit of zero {null sequence} c) having no members whatsoever {null set} [MFr nul < L nullus, not any, none < OL *n(e) oin(o)los, not a one < ne, not (see NO¹) + dim. of oinos < IE *oinos: see ONE]

nullah (nûl´э) •n. in India, etc., a watercourse, esp. one that is often dry; gully [Hindi nālā, brook, ravine]

nullification (nûl'э fi kei´shэn) •n. 1 a nullifying or being nullified Æ 2 in U.S. history, the refusal of a State to recognize or enforce within its territory any Federal law held to be an infringement on its sovereignty [LL(Ec) nullificatio, a despising]

nullifidian (nûl'э fid´i: эn) •n. a person having no religious faith [< L nullus, none + fides, FAITH + -IAN]

nullify (nûl´э fai') -fied', -fy'ing •vt. 1 to make legally null; make void; annul 2 to make valueless or useless; bring to nothing 3 to cancel out Æ nul´li·fi'er •n. [LL(Ec) nullificare, to despise < L nullus, none (see NULL) + facere, to make, DO¹]

nullipara (nûl lip´э rэ, nэ lip´-) pl. -a·ras or -a·rae' (-э ri:') •n. a woman who has never given birth to a child nul·lip´a·rous •adj. [ModL < L nullus, none (see NULL) + parere, to bring forth, bear: see -PAROUS]

nullipore (nûl´э pör') •n. any of several red-spored, coralline red algae that secrete lime [< L nullus, none (see NULL) + porus, PORE²]

nullity (nûl´э ti:) •n. 1 the state or fact of being null 2 pl. -ties anything that is null, as an act that has no legal force [Fr nullité < ML nullitas]

num 1 number 2 numeral(s) Num Bible Numbers

Numantia (nu: mæn´shi: э; nyu:-; -shэ) ancient city in what is now NC Spain: besieged & captured by Scipio the Younger (133 B.C.)

numb (nûm) •adj. 1 weakened in or deprived of the power of feeling or moving; benumbed; deadened; insensible {numb with cold, numb with grief} 2 having the nature of numbness {a numb feeling} •vt. to make numb numb´ly •adv. numb´ness •n. [< ME nome, nomen, pp. of nimen, to take (with unhistoric -b): see -NOMY]

numbat (nûm´bæt') •n. any of a family (Myrmecobiidae) of small, timid Australian marsupials that have no pouch

number (nûm´bэr) •n. 1 a symbol or word, or a group of either of these, showing how many or which one in a series: 1, 2, 10, 101 (one, two, ten, one hundred and one) are called cardinal numbers; 1st, 2d, 10th, 101st (first, second, tenth, one hundred and first) are called ordinal numbers 2 [pl.] ARITHMETIC 3 the sum or total of persons or units; aggregate 4 [with pl. v.] a collection of persons or things; company; assemblage {a small number of people} 5 a) [often pl.] a large group; many {cut down numbers of trees} b) [pl.] numerical superiority {safety in numbers} Æ c) [pl.] statistics, ratings, etc. {the pitcher's salary will be based on last year's numbers} 6 quantity, as consisting of units {a number of errors} 7 one of a series or group that is numbered or thought of as numbered; specif., a) a single issue of a periodical {the winter number of a quarterly} b) a single song, dance, skit, etc. in a program of entertainment Æ c) [Slang] a pattern of behavior or thought, esp. one characteristic of a particular individual, group, etc. 8 [Colloq.] a person or thing singled out {this hat is a smart number}: see also OPPOSITE NUMBER 9 Gram. a) a characteristic, as of nouns and verbs, indicating whether a given utterance involves reference to one or more than one entity, or, in some languages, to exactly two; also, an analytic category based on this characteristic b) the form a word takes to indicate this characteristic c) any of the sets of such forms: see SINGULAR, DUAL NUMBER, PLURAL 10 [pl.] [Obs.] a) metrical form; meter b) metrical lines; verses •vt. [ME nombren < OFr nombrer < L numerare, to count < numerus] 1 to total the number of persons or things in; count; enumerate 2 to give a number to; designate by number 3 to include as one of a group, class, or category {numbered among the missing} 4 to fix or limit the number or the duration of {his days are numbered} 5 to have or comprise; total {a library numbering 10,000 volumes} •vi. 1 to total; count; enumerate 2 to be numbered; be included a number of an unspecified number of; several or many beyond number too numerous to be counted Æ by the numbers 1 Mil. in prescribed sequence of movements and accompanied by a count 2 in a mechanical, unthinking way Æ do a number on [Slang] to abuse or mistreat in some way, as by injuring, disparaging, cheating, or humiliating Æ get (or have) someone's number [Slang] to discover (or know) someone's true character or motives Æ have someone's number on it [Slang] to be assumed to have been marked by fate for the person whom it kills: said of a bullet someone's number is up [Slang] someone's time to die or suffer punishment has arrived Æ the numbers an illegal lottery in which small bets are placed on the order of certain numbers, usually the last three, in some tabulation of game scores or financial reports published in the daily newspapers: also called numbers game (or racket) without number too numerous to be counted num´ber·er •n. [ME nombre < OE < L numerus: see -NOMY]

number cruncher (krûnch´эr) [Colloq.] a computer designed for, or a person capable of, the rapid execution of many or complex calculations (number crunching)

number one [Colloq.] 1 oneself Æ 2 the first, usually the very best, quality or grade

numberless (nûm´bэr lis) •adj. 1 innumerable; countless 2 without a number or numbers

Numbers (nûm´bэrz) the fourth book of the Pentateuch in the Bible, containing the census of the Hebrews after the Exodus: abbrev. Num, Nm, or Nu [transl. of Gr Arithmoi (see ARITHMETIC): from containing the census of the Hebrews after the Exodus]

numbfish (nûm´fish') pl. (see FISH) -fish' •n.or -fish'es an electric ray

numbles (nûm´bэlz) •n.pl. [Obs.] the heart, lungs, etc., as of a deer, used for food: cf. HUMBLE PIE [ME noumbles < OFr nombles, by dissimilation < L lumbulus, dim. of lumbus, loin: see LUMBAR]

numbskull (nûm´skûl') •n. NUMSKULL

numen (nu:´mэn, nyu:´-) pl. -mi·na (-mi nэ) •n. Rom. Myth. an indwelling, guiding force or spirit [L, a deity, akin to -nuere, to nod: see INNUENDO]

numerable (nu:´mэr э bэl, nyu:´-) •adj. that can be numbered or counted [L numerabilis]

numeral (nu:´mэr эl, nyu:´-) •adj. of, expressing, or denoting a number or numbers •n. 1 a figure, letter, or word, or a group of any of these, expressing a number: see ARABIC NUMERALS, ROMAN NUMERALS 2 [pl.] the numerals of the year of graduation of one's class in college, etc., awarded for participation in sports, etc. [LL numeralis < L numerus, NUMBER]

numerate¹ (nu:´mэr eit', nyu:´-) -at'ed, -at'ing •vt. 1 ENUMERATE 2 to read as words (numbers expressed in figures) [< L numeratus, pp. of numerare: see NUMBER & -ATE¹]

numerate² (nu:´mэr it, nyu:´-) •adj. [Chiefly Brit.] able to understand basic mathematical concepts and operations nu´mer·a·cy (-э si:) •n. [< L numerus, NUMBER + (LITER)ATE]

numeration (nu:'mэr ei´shэn, nyu:'-) •n. 1 a numbering or counting; calculation 2 a system of numbering 3 the act of numerating numbers expressed in figures [ME numeracioun < L numeratio < numerare: see NUMBER]

numerator (nu:´mэr eit'эr, nyu:´-) •n. 1 a person or thing that numbers 2 Math. the term above or to the left of the line in a fraction {6 is the numerator of 6/7} [LL < L numerare: see NUMBER]

numeric (nu: mer´ik, nyu:-) •adj. NUMERICAL •n. a numeral, or digit

numerical (nu: mer´i kэl, nyu:-) •adj. 1 of, or having the nature of, number 2 in or by numbers 3 denoting (a) number 4 expressed by numbers, not by letters 5 Math. designating or of value regardless of sign {the numerical value of -3 is 3} nu·mer´i·cal·ly •adv.

número uno (nu:´me řô u:´nô) [Colloq.] the very best or the most important one [Sp & It, lit., number one]

numerology (nu:'mэr äl´э ji:, nyu:'-) •n. a system of occultism built around numbers, esp. those giving birth dates, those which are the sum of the letters in one's name, etc.; divination by numbers [< L numerus, NUMBER + -LOGY]

numerous (nu:´mэr эs, nyu:´-) •adj. 1 consisting of many persons or things {a numerous collection} 2 very many nu´mer·ous·ly •adv. nu´mer·ous·ness •n. [L numerosus < numerus, NUMBER]

Numidia (nu: mid´i: э, nyu:-) ancient country in N Africa, mainly in what is now E Algeria [L < Numidae, the Numidians, pl. of numida, a nomad < Gr noumada, acc. of nomas, NOMAD]

Numidian (-эn) •n. 1 a native or inhabitant of Numidia 2 the language of old Berber inscriptions from this area •adj. of the Numidians or their culture

Numidian crane DEMOISELLE (sense 2)

numinous (nu:´mэ nэs, nyu:´-) •adj. 1 of or characteristic of a numen; supernatural; divine 2 having a deeply spiritual or mystical effect [< L numen (gen. numinis), a deity (see NUMEN) + -OUS]

numismatic (nu:'miz mæt´ik, nyu:'-; -mis-) •adj. 1 of coins, medals, or tokens 2 of or having to do with currency 3 of numismatics nu'mis·mat´i·cal·ly •adv. [Fr numismatique < L numisma (gen. numismatis), a coin < Gr nomisma, a coin, lit., what is sanctioned by law < nomizein, to sanction < nomos, law: see -NOMY]

numismatics (-iks) •n.pl. [with sing. v.] the study or collection of coins, medals, tokens, paper money, etc. nu·mis·ma·tist (nu: miz´mэ tist, nyu:-; -mis´-) •n. [see NUMISMATIC]

nummular (nûm´yu: lэr) •adj. coin-shaped; circular or oval [L nummularius < nummulus, dim. of nummus, a coin < Gr nomimos, legal < nomos: see -NOMY]

nummulite (nûm´yu: lait') •n. any of a genus (Nummulites) of nearly extinct foraminifera with a somewhat coin-shaped shell num'mu·lit´ic (-lit´ik) •adj. [< L nummus, a coin (see NUMMULAR) + -LITE]

numskull (nûm´skûl') •n. 1 a stupid person; dolt; dunce 2 [Archaic] the head of such a person [NUM(B) + SKULL]

nun¹ (nûn) •n. 1 a woman religious; sister; specif., such a woman under solemn vows 2 any of various birds; esp., any of a domesticated breed of pigeon [ME nunne < OE < LL(Ec) nonna, nun, orig., child's nurse: like Gr nanna, aunt, Sans nanā, mother, ult. < baby talk]

nun² (nu:n, nun) name of the fourteenth letter of the Hebrew alphabet (נ ן) •n. [Heb nūn, lit., fish]

nunatak (nûn´э tæk', nu:´nэ-) •n. Geol. an isolated mountain peak protruding through glacial ice [prob. via Dan < Esk]

Nunc Dimittis (nuŋk´ di mit´is) the song of Simeon, used as a canticle in various liturgies: Luke 2:29-32 [n- d-] a) departure or farewell, esp. from life b) permission to depart; dismissal [L, now thou lettest depart: first words of the L version]

nunciature (nûn´shi: э chэr, -si:-) •n. the office or term of office of a nuncio [It nunziatura]

nuncio (nûn´shou', -shi: ou'; -si: ou'; nun´tsi: ou') pl. -ci·os' •n. a prelate officially representing the pope and accredited to a foreign government [It nuncio, nunzio < L nuntius, messenger]

nuncle (nûŋ´kэl) •n. Brit. dial. or obs. var. of UNCLE [prob. < (a)n uncle or (mi)n(e) uncle]

nuncupative (nûn´kyu: peit'iv, also nûŋ´-; nûn kyu:´pэ tiv; also nûŋ-) •adj. oral, not written: said esp. of wills [LL nuncupativus, so-called, nominal < L nuncupare, to name before witnesses as one's heir < nomen, NAME + capere, to take: see HAVE]

nunnation (nû nei´shэn) •n. the addition of final n to a word, as in the declension of certain Arabic nouns [ModL nunnatio < Ar nūn, the letter n]

nunnery (nûn´эr i:) pl. -ner·ies •n. old term for CONVENT SYN. CLOISTER [ME nonnerie: see NUN¹ & -ERY]

nuptial (nûp´shэl, -chэl) •adj. 1 of marriage or a wedding 2 of or having to do with mating •n. [pl.] a wedding; marriage [LME nupcyalle < L nuptialis < nuptiae, marriage < nuptus, pp. of nubere, to marry: see NUBILE]

Nuremberg (nur´эm børg', nyur´-) city in SE Germany, in the state of Bavaria: pop. 472,000: Ger. name Nürn·berg (nüřn´beřk')

Nureyev (nu rei´yef), Rudolf (Hametovich) 1938-93; ballet dancer, born in the Soviet Union

nurse (nørs) •n. 1 WET NURSE 2 a woman hired to take full care of another's young child or children; nursemaid 3 a person trained to take care of the sick, injured, or aged, to assist surgeons, etc.; specif., a registered nurse or a practical nurse 4 a person or thing that nourishes, fosters, protects, etc. 5 Zool. a sexually incomplete worker bee or ant that cares for the young •vt. nursed, nurs´ing 1 to give milk from the breast to (an infant); suckle 2 to suck milk from the breast of 3 to take care of (a child or children) 4 to bring up; rear 5 to tend (the sick, injured, or aged) 6 to cause to continue, grow, or develop; nourish or foster {to nurse a grudge} 7 to treat, or try to cure {to nurse a cold} 8 a) to use, operate, or handle cautiously or carefully, so as to avoid injury, pain, exhaustion, etc. {to nurse an injured leg} b) to consume, spend, etc. slowly or carefully so as to conserve {to nurse a highball} 9 to clasp; hold carefully; fondle 10 Billiards to keep (the balls) close together for a series of caroms •vi. 1 to be suckled; feed at the breast 2 to suckle a child 3 to tend the sick, injured, etc. as a nurse nurs´er •n. [ME norse < OFr norice < LL nutricia < L nutricius, that suckles or nourishes < nutrix (gen. nutricis), wet nurse < nutrire, to nourish < IE *(s)neu-, var. of base *(s)nā-, to flow > NATANT, Sans snāuti, (she) gives milk, Gr naein, to flow]

nurse practitioner a registered nurse who has additional training and expertise in certain medical practices, therapies, etc.

nursemaid (nørs´meid') •n. a woman hired to take care of a child or children Also nurs´er·y·maid'

nursery (nørs´эr i:; often nørs´ri:) pl. -er·ies •n. 1 a) an infant's bedroom b) a room or apartment in a home, set apart for the children as a playroom, study, dining room, etc. 2 a place where parents may temporarily leave children with trained attendants; specif., a) NURSERY SCHOOL b) DAY NURSERY 3 a place where young trees or other plants are raised for experimental purposes, for transplanting, or for sale 4 anything that nourishes, protects, develops, or fosters [ME norcery: see NURSE]

nursery rhyme a short, rhymed, usually traditional poem for children

nursery school a school for very young children, usually three to five years of age

nurseryman (-mэn) pl. -men (-mэn) •n. a person who owns, operates, or works for a nursery for growing and transplanting trees, shrubs, etc.

nursing bottle a bottle with a rubber nipple, for feeding liquids to babies

nursing home 1 a residence equipped and staffed to provide care for the infirm, chronically ill, disabled, etc. 2 [Chiefly Brit.] a small private hospital

nursling (nørs´liŋ) •n. 1 a young baby still being nursed 2 anything that is being carefully tended or cared for Also nurse´ling

nurture (nør´chэr) •n. 1 anything that nourishes; food; nutriment 2 the act or process of raising or promoting the development of; training, educating, fostering, etc.: also nur´tur·ance 3 all the environmental factors, collectively, to which one is subjected from conception onward, as distinguished from one's nature or heredity •vt. -tured, -tur·ing 1 to feed or nourish 2 a) to promote the development of b) to raise by educating, training, etc. nur´tur·ant or nur´tur·al •adj. nur´tur·er •n. [ME < OFr norreture < LL nutritura, pp. of L nutrire, to nourish: see NURSE]

nut (nût) •n. 1 the dry, one-seeded fruit of any of various trees or shrubs, consisting of a kernel, often edible, in a hard and woody or tough and leathery shell, more or less separable from the seed itself, as the walnut, pecan, chestnut, acorn, etc. 2 the kernel, or meat, of such a fruit 3 loosely, any hard-shell fruit that will keep more or less indefinitely, as a peanut, almond, etc. 4 a small block, usually of metal, with a threaded hole through the center, for screwing onto a bolt, screw, etc. 5 a) a ridge of ebony or other hard material at the top of the fingerboard of a stringed instrument, over which the strings pass b) the small knob at the end of a violin bow, for tightening or loosening the hairs 6 [Colloq.] the initial cost of an undertaking, or the amount of money it is necessary to take in before a profit is realized on it 7 [Slang] a) the head b) [pl.] the testicles (a vulgar usage) 8 [Slang] a) a foolish, crazy, or eccentric person b) a devotee; fan 9 Printing EN (sense 2) See also NUTS •vi. nut´ted, nut´ting to hunt for or gather nuts hard (or tough) nut to crack a person, problem, or thing difficult to understand or deal with off one's nut [Slang] foolish, silly, or crazy [ME nutte < OE hnutu, akin to Ger nuss < IE *kneu-, lump, nut (< base *ken-, to squeeze together) > L nux, MIr cnū]

nut case [Slang] one who is eccentric or crazy Also nut·case (nût´keis') •n.

nut pine any of several pines, esp. a piñon, with edible seeds

nutant (nu:´tэnt, nyu:´-) •adj. with the top bent downward; drooping; nodding: said of plants [L nutans, prp. of nutare, to nod, freq. of nuere: for IE base see NUDGE]

nutation (nu: tei´shэn, nyu:-) •n. 1 the act or instance of nodding the head 2 a periodic variation in the inclination from the vertical of the rotation axis of a spinning body, as a top 3 Astron. such a small, periodic oscillation of the earth's axis which slightly varies or nods the earth's precessional motion 4 Bot. a slight rotatory movement, as in the stem of a plant, due to the varying rates of growth in its parts nu·ta´tion·al •adj. [L nutatio < nutare, to nod: see NUTANT]

nut-brown (nût´braun´) •adj. dark-brown, like some ripe nuts

nutcracker (nût´kræk'эr) •n. 1 an instrument for cracking the shells of nuts, usually consisting of two hinged metal levers, between which the nut is squeezed 2 either of two jaylike passerine birds (family Corvidae) that feed on nuts; specif., a white-spotted, dark-brown European bird (Nucifraga caryocatactes) or the grayish Clark's nutcracker (N. columbiana) of W North America

nutgall (nût´göl') •n. a small, nut-shaped gall on the oak and other trees

nuthatch (nût´hæch') •n. any of various small passerine birds (family Sittidae) with a sharp beak and a short tail, usually searching for insects by moving down tree trunks [ME notehach < note, nutte, NUT + *hache < hacken, HACK¹]

nutlet (nût´lit) •n. 1 a small nut or nutlike fruit 2 the pit, or stone, of a cherry, peach, plum, etc. 3 any of the segments of an ovary which splits into parts, as in plants of the borage and mint families

nutmeat (nût´mi:t') •n. the kernel of a nut, esp. if edible

nutmeg (nût´meg') •n. 1 the hard, aromatic seed of an East Indian tree (Myristica fragrans) of the nutmeg family: it is grated and used as a spice, and its outer covering yields the spice mace 2 the tree itself •adj. designating a family (Myristicaceae, order Magnoliales) of tropical, dicotyledonous trees [ME notemygge, partial transl. of OFr nois muguete < Prov noiz muscade, lit., musky nut < L nux, NUT + LL muscus, MUSK]

nutpick (nût´pik') •n. a small, sharp instrument for digging out the kernels of cracked nuts

nutria (nu:´tri: э, nyu:´-) •n. 1 the only member (Myocastor coypus) of a family (Myocastoridae) of South American water-dwelling rodents with webbed feet and a long, almost hairless tail; coypu 2 its short-haired, soft, brown fur, often dyed to look like beaver [Sp < L lutra, otter, altered (with l- after lutum, mire) < IE *udros, water animal: see OTTER]

nutrient (nu:´tri: эnt, nyu:´-) •adj. nutritious; nourishing •n. a nutritious ingredient or substance in a food [L nutriens, prp. of nutrire, to nourish: see NURSE]

nutriment (nu:´trэ mэnt, nyu:´-) •n. 1 anything that nourishes; food 2 anything that promotes growth, development, or good health [L nutrimentum < nutrire, to nourish: see NURSE]

nutrition (nu: trish´эn, nyu:-) •n. 1 a nourishing or being nourished; esp., the series of processes by which an organism takes in and assimilates food for promoting growth and replacing worn or injured tissues 2 anything that nourishes; nourishment; food 3 the science or study of proper, balanced diet to promote health, esp. in human beings nu·tri´tion·al •adj. nu·tri´tion·al·ly •adv. [MFr < L nutritio, nutricio < nutrix, NURSE]

nutritionist (-ist) •n. a specialist in nutrition

nutritious (nu: trish´эs, nyu:-) •adj. nourishing; of value as food nu·tri´tious·ly •adv. nu·tri´tious·ness •n. [L nutricius: see NURSE]

nutritive (nu:´trэ tiv, nyu:´-) •adj. 1 having to do with nutrition 2 promoting nutrition; nutritious nu´tri·tive·ly •adv. [ME nutritiff < OFr nutritif < ML nutritivus]

nuts (nûts) •adj. Æ [Slang] crazy; foolish Æ interj. [Slang] an exclamation of disgust, scorn, disappointment, refusal, etc.: often in the phrase nuts to someone (or something) be nuts about [Slang] 1 to be greatly in love with 2 to be very enthusiastic about [see NUT, 7 & 8]

nuts and bolts [Colloq.] the basic elements or practical aspects of something nuts´-and-bolts´ •adj.

nutshell (nût´shel') •n. the shell enclosing the kernel of a nut in a nutshell in brief or concise form; in a few words

nutting (nût´iŋ) •n. the act or process of gathering or hunting for nuts nut´ter •n.

nutty (nût´i:) -ti·er, -ti·est •adj. 1 containing or producing many nuts 2 having a nutlike flavor 3 [Slang] a) enthusiastic, often to excess b) queer, foolish, crazy, etc.: also nut·sy (nût´si:) nut´ti·ly •adv. nut´ti·ness •n.

nux vomica (nûks´ väm´i kэ) 1 the poisonous, disklike seed of an Asiatic tree (Strychnos nux-vomica) of the logania family, containing strychnine, brucine, and other alkaloids 2 the tree bearing these seeds 3 a medicine made from the seed, formerly used as a heart stimulant [ML < L nux, NUT + vomere, to VOMIT]

nuzzle (nûz´эl) -zled, -zling •vt. 1 to push against or rub with the nose, snout, muzzle, etc. 2 to root up with the nose or snout: said of a pig, etc. •vi. 1 to push or rub with the nose, etc. against or into something 2 to lie close; nestle; snuggle nuz´zler •n. [ME noselen < nose, NOSE + freq. -elen]

NV Nevada

NW 1 northwest 2 northwestern

NWbN northwest by north

NWbW northwest by west

NWT or NWTer Northwest Territories (Canada)

NY or N.Y. New York

nyala (nyä´lэ) pl. -la •n.or -las any of several antelopes (genus Tragelaphus) of E Africa, with large, spiral horns [< E African name]

Nyasa (nyä´sä, nai æs´э), Lake old name of Lake MALAWI

Nyasaland (-lænd') old name of MALAWI

NYC or N.Y.C. New York City

nyctalopia (nik'tэ lou´pi: э) •n. NIGHT BLINDNESS: cf. HEMERALOPIA nyc'ta·lop´ic (-läp´ik) •adj. [LL < Gr nyktalōps < nyx (gen. nyktos), NIGHT + alaos, blind (< a-, not + laein, to see) + ōps, EYE]

nycti- (nik´ti, -tэ) combining form night {nyctitropism} Also, before a vowel, nyct- [< Gr nyx (gen. nyktos), NIGHT]

nyctitropism (nik ti´trэ piz'эm) •n. the tendency of the leaves or petals of certain plants to assume a different position at night nyc'ti·trop´ic (-träp´ik) •adj. [prec. + -TROPISM]

nycto- (nik´tou, -tэ) combining form NYCTI- {nyctophobia}

nyctophobia (nik'tэ fou´bi: э) •n. an unnatural or excessive fear of darkness or night [prec. + -PHOBIA]

Nye (nai), Edgar Wilson (pseud. Bill Nye) 1850-96; U.S. humorist

nyet (nyet) •adv. no [Russ]

nylghai (nil´gai') •n. NILGAI

nylon (nai´län') •n. 1 any of a group of synthetic long-chain polymeric amides with recurring amide groups, made into fiber, yarn, bristles, sheets, molded plastics, etc. that have great strength and elasticity 2 a) any of the materials made from nylon b) [pl.] stockings of nylon yarn [arbitrary coinage, ? based on (VI)NYL + (RAY)ON]

nymph (nimf) •n. 1 Gr. & Rom. Myth. any of a group of minor nature goddesses, represented as young and beautiful and living in rivers, mountains, or trees 2 a) a lovely young woman b) a young woman; maiden: literary or playful usage 3 Entomology the young of an insect with incomplete metamorphosis, differing from the adult primarily in size and structural proportions nymph´al or nymph´e·an •adj. [ME nimphe < OFr < L nympha < Gr nymphē, young wife, spring goddess, hence (poetically) water: see NUBILE]

nymphalid (nim´fэ lid) •n. any of a family (Nymphalidae) of brightly colored butterflies with very short forelegs including the monarch and viceroy [< ModL Nymphalidae < Gr nymphē, nymph: see NUBILE]

nymphet (nim´fэt, nim fet´) •n. a pubescent girl, esp. one who is sexually precocious nym·phet´ic •adj. [Fr nymphette, dim. of nymphe: see NYMPH]

nympho (nim´fou) pl. -phos •adj., n. [Slang] short for NYMPHOMANIAC

nympholepsy (nim´fou lep'si:, -fэ-) •n. 1 in ancient times, a state of frenzy that was believed to seize any man who looked at a nymph 2 a violent emotional state arising as from frustrated idealism nym´pho·lept' •n. nym'pho·lep´tic •adj. [< Gr nympholēptos, seized by nymphs (< nymphē + -lēptos, seized < lambanein, to seize, assume: see LEMMA¹), infl. by EPILEPSY]

nymphomania (nim'fou mei´ni: э, -fэ-, -mein´yэ) •n. abnormal and uncontrollable desire by a woman for sexual intercourse: cf. SATYRIASIS nym'pho·ma´ni·ac' (-æk') •adj., n. [ModL < Gr nymphē, bride + -MANIA]

NYSE New York Stock Exchange

nystagmus (nis tæg´mэs) •n. an involuntary, rapid movement of the eyeball, usually from side to side nys·tag´mic •adj. [ModL < Gr nystagmos, drowsiness < nystazein, to be sleepy < IE base *sneud-, to sleep]

nystatin (nis´tэ tin) •n. an antibiotic, C46H77NO19, used for treating fungal infections, as candidiasis [N(ew) Y(ork) stat(e), where it was developed + -IN¹]

Nyx (niks) Gr. Myth. the goddess of night [Gr, NIGHT]

NZ or N Zeal New Zealand

O abbrev. 1 Ocean 2 October 3 Ohio 4 Physics ohm 5 Linguis. Old {OFr} 6 Ontario 7 Baseball out(s) 8 Chem. symbol for oxygen 9 pint [L octarius] o abbrev. 1 octavo 2 old 3 only

-o (ou) suffix 1 forming slangy, intensive counterparts of adjectives, nouns, and interjections {cheapo, freako} 2 forming slang nouns from adjectives {weirdo, sicko} [clipped < words ending in -o (e.g. HIPPO, STENO, GRINGO)]

-o- infix forming compound words: a connective vowel orig. used for combining Greek elements only, but now used freely {sadomasochism, meritocracy}

o' (ou, э) •prep. contr. of: 1 of {o'clock} 2 [Now Chiefly Dial.] on

O'- (ou) prefix descendant of: used in Irish surnames {O'Reilly} [Ir ō, descendant]

o- prefix ORTHO- (sense 4b): usually italicized and hyphenated in chemical names

O level 1 the first, or ordinary, level of standardized examinations in specific subjects taken by British secondary-school students seeking either a General Certificate of Education and university admission or a Certificate only 2 a pass on any examination at this level See A LEVEL Also O-level

o or O (ou) pl. o's, O's •n. 1 the fifteenth letter of the English alphabet: from the Greek omega and omicron, both borrowed from the Phoenician 2 any of the speech sounds that this letter represents, as, in English, the vowel (ou) of boat, (ä) of hot, or (ö) of wrong 3 a type or impression for O or o 4 the fifteenth in a sequence or group 5 an object shaped like O •adj. 1 of O or o 2 fifteenth in a sequence or group 3 shaped like O; circular or oval in shape

O tempora! O mores! (ou tem´pэ rэ ou mör´i:z') Oh, the times! Oh, the customs!: a quotation from Cicero [L]

O. Henry see HENRY, O.

o.c. in the work cited [L opere citato]

o.d. right eye [L oculus dexter]

o.s. left eye [L oculus sinister]

o/c overcharge

O/D or o/d 1 overdraft 2 overdrawn

O¹ (ou) pl. O's •n. 1 popularly, the figure zero; nought: in printed matter, zero is usually differentiated from the letter O, as in this dictionary: O is the character used for the letter, 0 is the character used for the number 2 a blood type: see ABO SYSTEM

O² (ou) •interj. an exclamation variously used: a) in direct address {O Lord!} b) to express surprise, fear, wonder, pain, etc. (now usually oh) c) at the end of a line in some ballads •n. pl. O's a use of this exclamation O and oh are now often interchangeable

oaf (ouf) •n. 1 orig., a changeling 2 a stupid person; specif., a stupid, clumsy fellow; lout oaf´ish •adj. oaf´ish·ly •adv. [earlier auf, ouphe < ON alfr, ELF]

Oahu (ou ä´hu:) chief island of Hawaii: 589 sq. mi. (1,526 sq. km); pop. 836,000; chief city, Honolulu [Haw]

oak (ouk) •n. 1 any of a genus (Quercus) of large hardwood trees and bushes of the beech family, bearing acorns 2 the wood of an oak 3 any of various plants with oaklike leaves 4 a wreath of oak leaves 5 woodwork, furniture, etc. made of oak •adj. of oak; oaken [ME oke < OE ac, akin to Ger eiche < IE base *aig-, oak > Gr aigilōps, a kind of oak]

oak apple an applelike gall on oak trees

Oak Lawn village in NE Ill.: suburb of Chicago: pop. 56,000 [after the many oak trees there]

Oak Park village in NE Ill.: suburb of Chicago: pop. 53,000 [see OAK LAWN]

Oak Ridge city in E Tenn., near Knoxville: center for atomic research: pop. 27,000 [see OAK LAWN]

oak tag tagboard used for posters, folders, etc. [OAK (because orig. made from oak fibers) + TAG(BOARD)]

oak wilt a disease of oaks which plugs the vessels of the wood and makes the leaves wilt, caused by an ascomycete fungus (Ceratocystis fagacearum)

oaken (ouk´эn) •adj. made of the wood of the oak

Oakland (ouk´lэnd) seaport in W Calif., on San Francisco Bay, opposite San Francisco: pop. 372,000 [after the oak groves orig. there]

oak-leaf cluster (ouk´li:f') a small, bronze cluster of oak leaves and acorns awarded to the holder of a U.S. Army or Air Force decoration for each new award of that decoration: a silver cluster equals five bronze clusters

oakum (ou´kэm) •n. loose, stringy hemp fiber gotten by taking apart old ropes and treated as with tar, used as a caulking material [ME okom < OE acumba, tow, oakum < a-, away, out + camb, COMB¹: lit., what is combed out]

Oakville (ouk´vil) town in SE Ontario, Canada, on Lake Ontario, near Toronto: pop. 87,000 [named for an oak stave industry there]

oar (ör) •n. 1 a long pole with a broad blade at one end, held in place by an oarlock and used in pairs to row a boat: a single oar is sometimes used in steering a boat 2 a person who uses an oar; rower •vt., vi. to row put one's oar in to meddle rest on one's oars to stop to rest or relax [ME ore < OE ar, akin to ON < IE *oyer-, rudder pole < base *ei-, *oi-, pole, rod > Gr oiēion, rudder]

oared (örd) •adj. equipped with oars: often used in hyphenated compounds {two-oared}

oarfish (ör´fish') pl. (see FISH) -fish' •n.or -fish'es any of a family (Regalecidae, order Lampriformes) of large, long, narrow, deep-sea bony fishes having a fin along the length of the back and a manelike crest behind the head: some reach a length of 9m (c. 29.5 ft.) and are responsible for many reports of sea serpents

oarlock (ör´läk') •n. a device, often U-shaped, for holding an oar in place in rowing

oarsman (örz´mэn) pl. -men (-mэn) •n. one who rows, esp. one who rows a racing shell oars´man·ship' •n.

OAS Organization of American States

oasis (ou ei´sis; also ou´э sis) pl. -ses' (-si:z') •n. 1 a fertile place in a desert, due to the presence of water 2 any place or thing offering welcome relief as from difficulty or dullness [L < Gr, fertile spot: orig. Coptic]

oast (oust) •n. a kiln for drying hops, malt, or tobacco [ME ost < OE ast < Gmc *aist- < IE base *ai-dh-, to burn > EDIFY]

oat (out) •n. 1 [usually pl.] a) a hardy, widely grown cereal grass (Avena sativa) b) the edible grain of this grass 2 any of various related grasses (genus Avena), esp. the wild oats 3 [Obs.] a simple musical pipe made of an oat stalk Æ feel one's oats [Slang] 1 to be in high spirits; be frisky 2 to feel and act important [ME ote < OE ate: not found in other Gmc languages: prob. < IE base *oid-, to swell > Russ jádrica, groats]

oat grass any of various oatlike grasses; esp., any of several grasses (genera Arrhenatherum and Danthonia) growing on hillsides and in woods

oatcake (-keik') •n. a thin, flat cake made of oatmeal

oaten (out´ªn) •adj. of or made of oats, oatmeal, or oat straw

oater (out´эr) •n. [Slang] WESTERN (n. 2) [from oats fed to horses]

Oates (outs), Titus 1649-1705; Eng. fabricator of the Popish Plot, a supposed Rom. Catholic plot (1678) to massacre Protestants, burn London, and kill the king

oath (ouθ) pl. oaths (ouðz, ouθs) •n. 1 a) a ritualistic declaration, typically based on an appeal to God or a god or to some revered person or object, that one will speak the truth, keep a promise, remain faithful, etc. b) the ritual form used in making such a declaration c) the thing promised or declared in this way 2 the irreverent or profane use of the name of God or of a sacred thing to express anger or emphasize a statement 3 a swearword; curse take oath to promise or declare by making an oath; swear solemnly under oath bound or obligated by having made a formal oath, as in a court of law [ME oth < OE ath, akin to Ger eid, prob. via Celt < IE *oitos (> OIr ōeth) < base *ei-, to go (basic sense: ? to advance to take an oath) > YEAR, L ire, to go]

oatmeal (out´mi:l') •n. 1 oats ground or rolled into meal or flakes 2 a porridge made from such oats

Oaxaca (wä hä´kä) 1 state of SE Mexico: 36,275 sq. mi. (93,952 sq. km); pop. 2,369,000 2 its capital: pop. 157,000

Ob (oub; Russ ôb´yª) 1 river in W Siberia, flowing from the Altai Mountains northwest & north into the Gulf of Ob: 2,495 mi. (4,015 km) 2 Gulf of arm of the Kara Sea, in NW Siberia: c. 600 mi. (966 km) long OB 1 obstetrician 2 obstetrics Ob Bible Obadiah

ob- (äb, эb) prefix 1 to, toward, before, in front of {obtrude} 2 opposed to, against {obstinate} 3 upon, over {obscure} 4 completely, totally {obdurate} 5 inversely, oppositely {obovoid} In words of Latin origin it becomes oc- before c; of- before f; o- before m; and op- before p [< L ob, toward, for, about, before < IE base *epi-, *opi-, near, at, toward, after > Gr epi]

ob. 1 he (or she) died [L obiit] 2 in passing; incidentally [L obiter]

Obadiah (ou'bэ dai´э) 1 a masculine name 2 a) Bible a Hebrew prophet b) the book of his prophecies (abbrev. Ob or Obad) [ult. < Heb ōbhadhyāh, lit., servant of the Lord]

obb obbligato

obbligato (äb'li gät´ou) •adj. Music not to be left out; indispensable: said earlier of an accompaniment essential to the proper performance of a piece, but now usually of one that can be omitted •n. pl. -tos or -ti (-i:) such a musical accompaniment [It, lit., obliged < L obligatus, pp. of obligare: see OBLIGE]

obconic (äb kän´ik) Bot. conical but attached by the point Also ob·con´i·cal •adj. [OB- + CONIC]

obcordate (äb'kör´deit') •adj. Bot. heart-shaped and joined to the stem at the apex: said of certain leaves [OB- + CORDATE]

obdurate (äb´dur it, -dyur-) •adj. 1 not easily moved to pity or sympathy; hardhearted 2 hardened and unrepenting; impenitent 3 not giving in readily; stubborn; obstinate; inflexible SYN. INFLEXIBLE ob´du·ra·cy (-э si:) •n. ob´du·rate·ly •adv. [ME < L obduratus, pp. of obdurare, to harden < ob-, intens. (see OB-) + durare, to harden < durus, hard: see DURESS]

OBE Officer (of the Order of the) British Empire

obeah (ou´bi: э) •n. [often O-] a form of magic or witchcraft practiced by natives of Guiana, and formerly also in parts of the South and in the West Indies [of WAfr orig.]

obedience (ou bi:´di: эns, э-; -bi:d´yэns) •n. 1 the state, fact, or an instance of obeying, or a willingness to obey; submission 2 Eccles. JURISDICTION [OFr < L obedientia < obediens]

obedient (ou bi:´di: эnt, э-; -bi:d´yэnt) •adj. obeying or willing to obey; submissive o·be´di·ent·ly •adv. SYN.—obedient suggests a giving in to the orders or instructions of one in authority or control [an obedient child]; docile implies a temperament that submits easily to control or that fails to resist domination [a docile servant]; tractable implies ease of management or control but does not connote the submissiveness of docile and applies to things as well as people [silver is a tractable, i.e., malleable, metal]; compliant suggests a weakness of character that allows one to yield meekly to another's request or demand [army life had made him compliant]; amenable suggests such amiability or desire to be agreeable as would lead one to submit readily [she is amenable to discipline] —ANT. disobedient, refractory [OFr < L obediens, prp. of obedire, OBEY]

obeisance (ou bei´sэns, -bi:´-) •n. 1 a gesture of respect or reverence, such as a bow or curtsy 2 the attitude shown by this; homage; deference o·bei´sant •adj. [ME obeisaunce < OFr obeissance < obeissant, prp. of obeir, OBEY]

obelisk (äb´э lisk; also ou´bэ-) •n. 1 a tall, slender, four-sided stone pillar tapering toward its pyramidal top 2 DAGGER (sense 2) [L obeliscus < Gr obeliskos, a small spit, obelisk, dim. of obelos: see OBELUS]

obelize (äb´э laiz') -lized', -liz'ing •vt. to mark with an obelus [Gr obelizein]

obelus (äb´э lэs) pl. -li' (-lai') •n. 1 a mark (- or ÷) used in ancient manuscripts to indicate questionable passages or readings 2 DAGGER (sense 2) [ME < L, a spit, obelus (in LL, obelisk) < Gr obelos, a spit, needle, obelus, obolus]

Oberammergau (ou'bэř äm´эř gau') village in S Germany, in the state of Bavaria: site of a Passion play performed usually every ten years: pop. 4,700

Oberhausen (ou´bэř hau'zªn) city in WC Germany, in the state of North Rhine-Westphalia: pop. 224,000

Oberland (ou´bэř länt') BERNESE ALPS

Oberon (ou´bэr än', -эn') Eng. Folklore the king of fairyland and husband of Titania [Fr < OFr Auberon < Gmc base of ELF, OAF]

obese (ou bi:s´) •adj. very fat; stout; corpulent o·be´si·ty •n. [L obesus, pp. of obedere, to devour < ob- (see OB-) + edere, EAT]

obey (ou bei´, э-) •vt. 1 to carry out the instructions or orders of 2 to carry out (an instruction or order) 3 to be guided by; submit to the control of {to obey one's conscience} •vi. to be obedient o·bey´er •n. [ME obeien < OFr obeir < L obedire, to obey < OL oboedire < ob- (see OB-) + audire, to hear: see AUDIENCE]

obfuscate (äb fûs´keit', äb´fэs keit') -cat'ed, -cat'ing •vt. 1 to cloud over; obscure; make dark or unclear 2 to muddle; confuse; bewilder ob'fus·ca´tion •n. [< L obfuscatus, pp. of obfuscare, to darken < ob- (see OB-) + fuscare, to obscure < fucus, dark < IE base *dhus- > DUSK, DOZE, DUST]

OB-GYN, OB-Gyn, or Ob-Gyn 1 obstetrical-gynecological 2 obstetrician-gynecologist 3 obstetrics-gynecology

obi¹ (ou´bi:) •n. OBEAH

obi² (ou´bi:) •n. a broad sash with a bow in the back, worn with a Japanese kimono [Jpn]

Obie (ou´bi:) •n. any of the awards made annually in the U.S. for special achievements in off-Broadway productions [< O(FF-)B(ROADWAY) + -IE]

obit (ou´bit; also äb´it) •n. OBITUARY [ME obite < OFr obit < L obitus, death < pp. of obire, to fall, die < ob- (see OB-) + ire, to go: see YEAR]

obiter dictum (äb´i tэr dik´tэm, ou´bi-) pl. ob´i·ter dic´ta (-tэ) 1 DICTUM (n. 2) 2 any incidental remark [L, (something) said incidentally: obiter, incidentally (< ob: see OB- + (circ)iter, near < circa, about) + dictum, DICTUM]

obituary (ou bich´u: er'i:, э-) pl. -ar'ies •n. a notice of someone's death, as in a newspaper, usually with a brief biography •adj. of or recording a death or deaths o·bit´u·ar'ist •n. [ML obituarius < L obitus: see OBIT]

obj 1 object 2 objection 3 objective

object (for n. äb´jikt; for v. эb jekt´, äb-) •n. 1 a thing that can be seen or touched; material thing that occupies space 2 a person or thing to which action, thought, or feeling is directed 3 what is aimed at; purpose; end; goal 4 Gram. a noun or other substantive that directly or indirectly receives the action of a verb, or one that is governed by a preposition {in Give me the book, book is the direct object and me is the indirect object} 5 Philos. anything that can be known or perceived by the mind •vt. 1 [Archaic] a) to oppose b) to thrust in; interpose c) to expose d) to bring forward as a reason, instance, etc.; adduce 2 to put forward in opposition; state by way of objection {it was objected that the new tax law was unfair} •vi. 1 to put forward an objection or objections; enter a protest; be opposed 2 to feel or express disapproval or dislike ob´ject·less •adj. ob·jec´tor •n. SYN.—object implies opposition to something because of strong dislike or disapproval [I object to her meddling]; protest implies the making of strong, formal, often written objection to something [they protested the new tax increases]; remonstrate implies protest and argument in demonstrating to another that he or she is wrong or blameworthy [he remonstrated against her hostile attitude]; expostulate suggests strong, earnest pleading or argument to change another's views or actions [I expostulated with him about his self-sacrifice]; demur implies the raising of objections or the taking of exception so as to delay action [I demurred at her proposal to dine out] see also INTENTION —ANT. agree, consent, acquiesce [ME < ML objectum, something thrown in the way < L objectus, a casting before, that which appears, orig. pp. of objicere < ob- (see OB-) + jacere, to throw: see JET¹]

object ball Billiards, Pool any ball other than the cue ball

object glass OBJECTIVE (n. 4)

object lesson an actual or practical demonstration or exemplification of some principle

objectify (эb jek´tэ fai', äb-) -fied', -fy'ing •vt. to give objective form to; make objective or concrete; externalize ob·jec'ti·fi·ca´tion •n. [OBJECT + -I- + -FY]

objection (эb jek´shэn, äb-) •n. 1 the act of objecting 2 a feeling or expression of opposition, disapproval, or dislike 3 a cause for objecting; reason for opposing, disapproving, or disliking [ME objeccioun < LL objectio < L objectus: see OBJECT]

objectionable (-э bэl) •adj. 1 open to objection 2 disagreeable; offensive ob·jec´tion·a·bly •adv.

objective (эb jэk´tiv, äb-) •adj. 1 of or having to do with a known or perceived object as distinguished from something existing only in the mind of the subject, or person thinking 2 being, or regarded as being, independent of the mind; real; actual 3 determined by and emphasizing the features and characteristics of the object, or thing dealt with, rather than the thoughts and feelings of the artist, writer, or speaker {an objective painting or description} 4 without bias or prejudice; detached 5 being the aim or goal {an objective point} Æ 6 designating a kind of test, as a multiple-choice or true-false test, that minimizes subjective factors in answering and grading 7 Gram. designating or of the case of an object of a transitive verb or preposition 8 Med. designating or of a symptom or condition perceptible to others besides the patient •n. 1 anything external to or independent of the mind; something objective; reality 2 something aimed at or striven for 3 Gram. a) the objective case b) a word in this case 4 Optics the lens or lenses nearest to the object observed, as in a microscope or telescope, that focuses light to form the image of the object: see MICROSCOPE, illus. SYN. FAIR¹, INTENTION ob·jec´tive·ly •adv. ob·jec´tive·ness •n. [ML objectivus]

objective complement a word or group of words used in the predicate of a sentence as a modifier or qualifier of the direct object (Ex.: president in We elected him president)

objective correlative a sequence of events, cluster of images, setting, etc. employed in a literary work to express a certain emotion and evoke it in the reader or viewer

objectivism (эb jek´tiv iz'эm, äb-) •n. 1 any of various philosophical doctrines that stress the external, independent existence of what is perceived or known 2 an ethical theory maintaining that the validity of ethical assertions can be determined objectively 3 the use of objective methods in art or literature ob·jec´tiv·ist •n., adj. ob·jec'tiv·is´tic •adj.

objectivity (äb'jek tiv´э ti:) •n. 1 the state or quality of being objective 2 objective reality

objectivize (эb jek´tэ vaiz', äb-) -ized', -iz'ing •vt. OBJECTIFY ob·jec'ti·vi·za´tion •n.

objet d'art (ôb'zhei där´, äb'-) pl. ob'jets d'art´ (-zhei-) a relatively small object of artistic value, as a figurine, vase, etc. [Fr, lit., object of art]

objet trouvé (ôb zhэ třu: vei´) pl. ob·jets trou·vés (ôb zhe třu: vei´) an ordinary object, as a piece of driftwood, a shell, or a manufactured article, that is treated as an object of art by one who finds it aesthetically pleasing [Fr, found object]

objurgate (äb´jэr geit', эb jør´geit') -gat'ed, -gat'ing •vt. to chide vehemently; upbraid sharply; rebuke; berate ob'jur·ga´tion •n. ob´jur·ga'tor •n. ob·jur´ga·to'ry (-gэ tör'i:) •adj. [< L objurgatus, pp. of objurgare, to rebuke, chastise < ob- (see OB-) + jurgare, to chide, orig., to sue at law < jus (gen. juris: see JURY¹) + agere, to do, ACT]

obl 1 oblique 2 oblong

oblanceolate (äb læn´si: э lit, -leit') •adj. lance-shaped, with the broad end at the top: said of a leaf [OB- + LANCEOLATE]

oblast (äb´læst) •n. an administrative subdivision, or region, of a republic in the U.S.S.R. [Russ oblast']

oblate¹ (äb´leit', äb leit´) •adj. Geom. flattened at the poles {an oblate spheroid} [ModL oblatus < OB- + -latus as in prolatus (see PROLATE): from being thrust forward at the equator]

oblate² (äb´leit') •n. R.C.Ch. a person dedicated to the religious life; esp., a person living in or associated with a religious community but not bound by vows [ML oblatus, offered, thrust forward < pp. of L offerre: see OFFER]

oblation (э blei´shэn, äb lei´-) •n. 1 an offering of a sacrifice, thanksgiving, etc. to God or a god 2 the thing or things offered; esp., the bread and wine of the Eucharist ob·la´tion·al or ob·la·to·ry (äb´lэ tör'i:) •adj. [ME oblacioun < OFr oblation < L oblatio, an offering < oblatus: see OBLATE2]

obligate (for v. äb´lэ geit'; for adj., -git, -geit') -gat'ed, -gat'ing •vt. to bind by a contract, promise, sense of duty, etc.; put under obligation •adj. [ME < L obligatus] 1 bound; obliged 2 Biol. limited to a certain condition of life, as some parasites [< L obligatus, pp. of obligare: see OBLIGE]

obligation (äb'lэ gei´shэn) •n. 1 an obligating or being obligated 2 a binding contract, promise, moral responsibility, etc. 3 a duty imposed legally or socially; thing that one is bound to do by contract, promise, moral responsibility, etc. 4 the binding power of a contract, promise, etc. 5 a) the condition or fact of being indebted to another for a favor or service received b) a favor or service 6 Law a) an agreement or duty by which one person (the obligor) is legally bound to make payment or perform services for the benefit of another (the obligee) b) the bond, contract, or other document setting forth the terms of this agreement ob'li·ga´tion·al •adj. [ME obligacioun < OFr obligation < L obligatio]

obligato (äb'li gät´ou) pl. -tos or -ti (-i:) •adj., n. OBBLIGATO

obligatory (эb lig´э tör'i:, äb´lэ gэ-) •adj. 1 legally or morally binding; constituting, or having the nature of, an obligation; required 2 Biol. OBLIGATE ob·lig´a·to'ri·ly •adv. [LL obligatorius]

oblige (э blaij´, ou-) o·bliged´, o·blig´ing •vt. 1 to compel by moral, legal, or physical force; constrain 2 to make indebted for a favor or kindness done; do a favor for •vi. to do a favor or service o·blig´er •n. [ME obligen < OFr obligier < L obligare, to bind, oblige < ob- (see OB-) + ligare, to bind: see LIGATURE]

obligee (äb'lэ ji:´) •n. 1 a person obliged to do something for another 2 Law a person to whom another is bound by contract [< prec. + -EE¹]

obliging (э blai´jiŋ, ou-) •adj. ready to do favors; helpful; courteous; accommodating o·blig´ing·ly •adv.

obligor (äb'lэ gör´, äb´lэ gör') •n. Law a person who binds himself to another by contract [< OBLIGE + -OR]

oblique (э bli:k´, ou-; also, esp. in mil. use, -blaik´) •adj. 1 having a slanting position or direction; neither perpendicular nor horizontal; not level or upright; inclined 2 not straight to the point; not straightforward; indirect 3 evasive, disingenuous, underhanded, etc. 4 indirectly aimed at or attained {oblique results} 5 Anat. designating or of any of certain muscles obliquely placed and attached 6 Bot. having the sides unequal, as some leaves 7 Geom. with its axis not perpendicular to its base {an oblique cone} 8 Gram. designating or of any case except the nominative and the vocative •n. an oblique angle, muscle, etc. •vi. ob·liqued´, ob·liqu´ing to veer from the perpendicular; slant •adv. Mil. with a change of direction of approximately 45 degrees ob·lique´ly •adv. ob·lique´ness •n. [ME oblike < L obliquus < ob- (see OB-) + liquis, awry < IE *leik-, var. of base *elei-, to bend > ELL²]

oblique angle any angle other than a right angle; acute or obtuse angle

obliquity (э blik´wэ ti:) pl. -ties •n. 1 the state or quality of being oblique 2 an oblique statement, action, etc. 3 a turning aside from moral conduct or sound thinking 4 Astron. the angle between the planes of a planet's equator and its orbit about the sun: for the earth (obliquity of the ecliptic) it is currently c. 23° 26.5' and will decrease at the rate of 0.47" a year for c. 1,500 years, at which time it will begin to increase again 5 Math. a) deviation of a line or plane from the perpendicular or parallel b) the degree of this ob·liq´ui·tous •adj. [ME obliquitee < L obliquitas]

obliterate (э blit´эr eit') -at'ed, -at'ing •vt. 1 to blot out or wear away, leaving no traces; erase; efface 2 to do away with as if by effacing; destroy SYN. ERASE ob·lit'er·a´tion •n. ob·lit´er·a'tive •adj. ob·lit´er·a'tor •n. [< L obliteratus, pp. of obliterare, to blot out < ob- (see OB-) + littera, LETTER¹]

oblivion (э bliv´i: эn) •n. 1 a forgetting or having forgotten; forgetfulness 2 the condition or fact of being forgotten 3 official overlooking of offenses; pardon [OFr < L oblivio < oblivisci, to forget < ob- (see OB-) + (prob.) levis, smooth < IE base *lei-, slippery > LIME¹]

oblivious (э bliv´i: эs) •adj. 1 forgetful or unmindful: usually with of or to 2 causing forgetfulness ob·liv´i·ous·ly •adv. ob·liv´i·ous·ness •n. [ME obliuyous < L obliviosus < oblivio; see OBLIVION]

oblong (äb´löŋ') •adj. longer than broad; elongated; specif., a) rectangular and longer in one direction than in the other, esp. longer horizontally b) elliptical •n. an oblong figure [ME oblonge < L oblongus, rather long < ob- (see OB-) + longus, LONG¹]

obloquy (äb´lэ kwi:) pl. -quies •n. 1 verbal abuse of a person or thing; censure or vituperation, esp. when widespread or general 2 ill repute, disgrace, or infamy resulting from this [ME obliqui < LL obloquium < L obloqui, to speak against < ob- (see OB-) + loqui, to speak]

obnoxious (эb näk´shэs, äb-) •adj. 1 orig., a) exposed or liable to injury, evil, or harm b) liable to punishment; censurable 2 very unpleasant; objectionable; offensive SYN. HATEFUL ob·nox´ious·ly •adv. ob·nox´ious·ness •n. [L obnoxiosus < obnoxius, subject or exposed to danger < ob- (see OB-) + noxa, harm < base of nocere, to hurt: see NECRO-]

oboe (ou´bou) •n. 1 a double-reed woodwind instrument having a range of nearly three octaves and a high, penetrating, melancholy tone 2 an organ stop producing an oboelike sound o´bo·ist •n. [It < Fr hautbois; see HAUTBOY]

obolus (äb´э lэs) pl. -li' (-ai') •n. 1 in ancient Greece a) a coin valued at ¹/6 drachma b) a weight equal to 11¼ grains 2 any of several small coins formerly current in Europe Also ob´ol [L < Gr obolos, var. of obelos, a spit, needle, bar used as money]

obovate (äb ou´veit') •adj. inversely ovate; having the shape of the longitudinal section of an egg, with the broad end at the top, as some leaves: see LEAF, illus.

obovoid (äb ou´void') •adj. egg-shaped, with the broad end at the top: said of some fruits, etc. [OB- + OVOID]

obs 1 obscure 2 obsolete 3 observation 4 observatory

obscene (äb si:n´, эb-) •adj. 1 offensive to one's feelings, or to prevailing notions, of modesty or decency; lewd 2 disgusting; repulsive 3 Law designating or of books, films, etc. which when judged by contemporary community standards, are found to appeal to a prurient interest in sex, be patently offensive, and have no serious artistic, scientific, or social value SYN. COARSE ob·scene´ly •adv. [Fr obscène < L obscenus, obscaenus < obs-, var. of ob- (see OB-) + caenum, filth < IE *weino- < base *kwei-, muck, filth > ON hvein, swampy land]

obscenity (äb sen´э ti:, эb-; chiefly Brit, also, -si:n´-) •n. 1 the state or quality of being obscene 2 pl. -ties an obscene remark, act, event, etc. [Fr obscénité < L obscenitas]

obscurant (äb skyur´эnt, эb-) •n. a person or thing that obscures, esp. one that opposes or tends to prevent human progress and enlightenment •adj. that obscures; of or constituting an obscurant: also ob·scu·ran·tic (äb'skyu: ræn´tik) [< L obscurantem, acc. of obscurans, prp. of obscurare, to OBSCURE]

obscurantism (äb skyur´эn tiz'эm, эb-) •n. 1 opposition to human progress or enlightenment 2 the practice of being deliberately obscure or vague ob·scur´ant·ist •n., adj.

obscuration (äb'skyu: rei´shэn) •n. an obscuring or being obscured [L obscuratio]

obscure (эb skyur´, äb-) •adj. 1 lacking light; dim; dark; murky {the obscure night} 2 not easily perceived; specif., a) not clear or distinct; faint or undefined {an obscure figure or sound} b) not easily understood; vague; cryptic; ambiguous {an obscure explanation} c) in an inconspicuous position; hidden {an obscure village} 3 not well-known; not famous {an obscure scientist} 4 Phonet. pronounced as (э) or (i) because it is not stressed; reduced; neutral: said of a vowel •vt. -scured´, -scur´ing [L obscurare < the adj.] 1 to make obscure; specif., a) to darken; make dim b) to conceal from view; hide c) to make less conspicuous; overshadow {a success that obscured earlier failures} d) to make less intelligible; confuse {testimony that obscures the issue} 2 Phonet. to make (a vowel) obscure •n. [Rare] OBSCURITY ob·scure´ly •adv. ob·scure´ness •n. SYN.—obscure applies to that which is perceived with difficulty either because it is concealed or veiled or because of obtuseness in the perceiver [their reasons remain obscure]; vague implies such a lack of precision or exactness as to be indistinct or unclear [a vague idea]; enigmatic and cryptic are used of that which baffles or perplexes, the latter word implying deliberate intention to puzzle [enigmatic behavior, a cryptic warning]; ambiguous applies to that which puzzles because it allows of more than one interpretation [an ambiguous title]; equivocal is used of something ambiguous that is deliberately used to mislead or confuse [an equivocal answer] —ANT. clear, distinct, obvious [OFr obscur < L obscurus, lit., covered over < ob- (see OB-) + IE *skuro- < base *(s)keu-, to cover, conceal > HIDE¹, SKY]

obscurity (-skyur´э ti:) •n. 1 the quality or condition of being obscure 2 pl. -ties an obscure person or thing

obsecrate (äb´si kreit') -crat'ed, -crat'ing •vt. [Rare] to beg for (something) or supplicate (someone); entreat ob'se·cra´tion •n. [< L obsecratus, pp. of obsecrare, to beseech (on religious grounds) < ob- (see OB-) + sacrare: see SACRED]

obsequies (äb´si kwi:z') •n.pl. funeral rites or ceremonies [< obs. sing. obsequy < OFr obseques < ML obsequiae (pl.) (< L obsequium, compliance: see OBSEQUIOUS), substituted for L exsequiae: see EXEQUIES]

obsequious (эb si:´kwi: эs, äb-) •adj. 1 showing too great a willingness to serve or obey; fawning 2 [Archaic] compliant; dutiful ob·se´qui·ous·ly •adv. ob·se´qui·ous·ness •n. [ME obsequyouse < L obsequiosus < obsequium, compliance < obsequi, to comply with < ob- (see OB-) + sequi, to follow: see SEQUENT]

observable (эb zørv´э bэl) •adj. 1 that can be observed; visible; discernible; noticeable 2 deserving of attention; noteworthy 3 that can or must be kept or celebrated {an observable holiday} ob·serv´a·bly •adv. [L observabilis]

observance (эb zørv´эns) •n. 1 the act or practice of observing, or keeping, a law, duty, custom, rule, etc. 2 a customary act, rite, ceremony, etc. 3 the act of observing, or noting; observation 4 [Archaic] respectful attention; deference 5 R.C.Ch. a) the rule observed by a religious order b) the order observing a specified rule [ME observaunce < OFr observance < L observantia, attention, regard, in LL(Ec), divine worship]

observant (эb zørv´эnt) •adj. 1 strict in observing, or keeping, a law, custom, duty, rule, etc.: often with of {observant of the rules of etiquette} 2 paying careful attention; keenly watchful 3 perceptive or alert •n. [O-] former name for FRIAR MINOR ob·serv´ant·ly •adv. [Fr, prp. of observer, OBSERVE]

observation (äb'zэr vei´shэn) •n. 1 orig., observance, as of laws, customs, etc. 2 a) the act, practice, or power of noticing b) something noticed 3 the fact of being seen or noticed {seeking to avoid observation} 4 a) the act or practice of noting and recording facts and events, as for some scientific study b) the data so noted and recorded 5 a comment or remark based on something observed 6 a) the act of determining the altitude of the sun, a star, etc., in order to find a ship's position at sea b) the result obtained •adj. for observing SYN. REMARK [ME observacioun < L observatio, in LL(Ec), reverence, outward display]

observation car a railway car with extra-large windows or a transparent dome for facilitating a view of the scenery

observation post an advanced military position from which movements of the enemy can be observed, artillery fire directed, etc.

observational (-shэ nэl) •adj. of or based on observation rather than experimentation

observatory (эb zørv´э tör'i:) pl. -ries •n. 1 a) a building equipped for scientific observation, esp. such a building with a large telescope for astronomical research b) an institution for such research 2 any building or place providing an extensive view of the surrounding terrain [ModL observatorium < pp. of L observare: see OBSERVE]

observe (эb zørv´) -served´, -serv´ing •vt. 1 to adhere to, follow, keep, or abide by (a law, custom, duty, rule, etc.) 2 to celebrate or keep (a holiday, etc.) according to custom 3 a) to notice or perceive (something) b) to pay special attention to 4 to arrive at as a conclusion after study 5 to say or mention casually; remark 6 to examine and study scientifically •vi. 1 to take notice 2 to comment or remark (on or upon) 3 to act as an observer SYN. DISCERN, CELEBRATE ob·serv´ing·ly •adv. [ME observen < OFr observer < L observare, to watch, note < ob- (see OB-) + servare, to keep or hold < IE base *ser-, to watch over, guard > Sans haraiti, (he) guards]

observer (эb zørv´эr) •n. 1 a person who observes something; specif., a) a soldier manning an observation post b) a person who attends an assembly, convention, etc., not as an official delegate but only to observe and report the proceedings c) an official, usually a member of a group, sent by a UN committee to collect and report facts on the situation in a special area 2 a member of an aircraft crew, other than a pilot, with certain specialized duties and a special rating (aircraft observer)

obsess (эb ses´) •vt. to haunt or trouble in mind, esp. to an abnormal degree; preoccupy greatly [< L obessus, pp. of obsidere, to besiege < ob- (see OB-) + sedere, SIT]

obsession (эb sesh´эn) •n. 1 orig., the act of an evil spirit in possessing or ruling a person 2 a) the fact or state of being obsessed with an idea, desire, emotion, etc. b) such a persistent idea, desire, emotion, etc., esp. one that cannot be gotten rid of by reasoning ob·ses´sion·al •adj. [L obsessio]

obsessive (эb ses´iv) •adj. of, having the nature of, or causing an obsession or obsessions •n. a person who has obsessive thoughts ob·ses´sive·ly •adv. ob·ses´sive·ness •n.

obsessive-compulsive neurosis a neurosis characterized by compulsive ideas or irresistible urges, or both, and often manifested in the ritualistic performance of certain acts

obsidian (эb sid´i: эn) •n. a hard, usually dark-colored or black, volcanic glass with conchoidal fracture, often used as a gemstone [ModL obsidianus < L Obsidianus (lapis), a faulty reading in PLINY (altered by assoc. with L obsidium, a siege < obsidere: see OBSESS) for Obsianus (lapis), stone of Obsius, finder of a similar stone in Ethiopia]

obsolesce (äb'sэ les´) -lesced´, -lesc´ing •vi. to be or become obsolescent [L obsolescere: see OBSOLETE]

obsolescent (äb'sэ les´эnt) •adj. in the process of becoming obsolete ob'so·les´cence •n. ob'so·les´cent·ly •adv. [L obsolescens]

obsolete (äb´sэ li:t', äb'sэ li:t´) •adj. 1 no longer in use or practice; discarded 2 no longer in fashion; out-of-date; passé 3 Biol. rudimentary or poorly developed as compared with its counterpart in other individuals of a related species, the opposite sex, etc.; vestigial: said of an organ, etc. •vt. -let'ed, -let'ing to make obsolete, as by replacing with something newer SYN. OLD ob´so·lete'ly •adv. ob´so·lete'ness •n. [L obsoletus, pp. of obsolescere, to go out of use < ob- (see OB-) + *-solescere (< exolescere, to grow out of use < ex-, EX-¹ + ? alescere, to increase: see ADOLESCENT]

obstacle (äb´stэ kэl) •n. anything that gets in the way or hinders; impediment; obstruction; hindrance SYN.—obstacle is used of anything which literally or figuratively stands in the way of one's progress [her father's opposition remained their only obstacle]; impediment applies to anything that delays or retards progress by interfering with the normal action [a speech impediment]; obstruction refers to anything that blocks progress or some activity as if by stopping up a passage [your interference is an obstruction of justice]; hindrance applies to anything that thwarts progress by holding back or delaying [lack of supplies is the greatest hindrance to my experiment]; barrier applies to any apparently insurmountable obstacle that prevents progress or keeps separate and apart [language differences are often a barrier to understanding] [OFr < L obstaculum, obstacle < obstare, to withstand < ob- (see OB-) + stare, to STAND]

obstetric (эb ste´trik, äb-) •adj. of childbirth or obstetrics Also ob·stet´ri·cal ob·stet´ri·cal·ly •adv. [ModL obstetricus, for L obstetricius, belonging to a midwife < obstetrix, midwife, lit., she who stands before < ob- (see OB-) + stare, to STAND]

obstetrician (äb'stэ trish´эn) •n. a medical doctor who specializes in obstetrics

obstetrics (эb ste´triks, äb-) •n.pl. [with sing. v.] the branch of medicine concerned with the care and treatment of women during pregnancy, childbirth, and the ensuing period [< OBSTETRIC]

obstinacy (äb´stэ nэ si:) •n. 1 the state or quality of being obstinate; specif., a) stubbornness b) resistance to treatment; persistence, as of a disease 2 pl. -cies an obstinate act, attitude, etc. [ME obstinacie < ML obstinatia, for L obstinatio]

obstinate (äb´stэ nэt) •adj. 1 unreasonably determined to have one's own way; not yielding to reason or plea; stubborn; dogged; mulish 2 resisting remedy or treatment {an obstinate fever} 3 not easily subdued, ended, etc. SYN. STUBBORN ob´sti·nate·ly •adv. ob´sti·nate·ness •n. [ME < L obstinatus, pp. of obstinare, to resolve on < obstare, to stand against, oppose < ob- (see OB-) + stare, to STAND]

obstipation (äb'stэ pei´shэn) •n. Med. severe and persistent constipation [L obstipatio < L ob- (see OB-) + stipare, to cram, pack: see STIFF]

obstreperous (eb strep´эr эs, äb-) •adj. noisy, boisterous, or unruly, esp. in resisting or opposing SYN. VOCIFEROUS ob·strep´er·ous·ly •adv. ob·strep´er·ous·ness •n. [L obstreperus < obstrepere, to roar at < ob- (see OB-) + strepere, to roar < IE base *(s)trep-, to make a loud noise > OE thræft, strife]

obstruct (эb strûkt´) •vt. 1 to block or stop up (a passage) with obstacles or impediments; dam; clog 2 to hinder (progress, an activity, etc.); impede 3 to cut off from being seen; block (the view) SYN. HINDER¹ ob·struct´er or ob·struc´tor •n. [< L obstructus, pp. of obstruere, to block up, build against < ob- (see OB-) + struere, to pile up: see STREW]

obstruction (эb strûk´shэn) •n. 1 an obstructing or being obstructed 2 anything that obstructs; hindrance SYN. OBSTACLE [L obstructio]

obstructionist (-ist) •n. anyone who obstructs progress; esp., a member of a legislative group who hinders the passage of legislation by various technical maneuvers •adj. of obstructionists or obstructionism: also ob·struc'tion·is´tic ob·struc´tion·ism' •n.

obstructive (эb strûk´tiv) •adj. obstructing or tending to obstruct ob·struc´tive·ly •adv. ob·struc´tive·ness •n.

obstruent (äb´stru: эnt) •adj. [Rare] obstructing; esp., blocking a passage of the body •n. [Rare] something, as a kidney stone, that blocks a passage of the body [L obstruens, prp. of obstruere, to block up: see OBSTRUCT]

obtain (эb tein´) •vt. 1 to get possession of, esp. by some effort; procure 2 [Archaic] to arrive at; reach or achieve •vi. 1 to be in force or in effect; prevail {a law that no longer obtains} 2 [Archaic] to succeed SYN. GET ob·tain´a·ble •adj. ob·tain´er •n. ob·tain´ment •n. [ME obteinen < OFr obtenir < L obtinere, to obtain, prevail, maintain < ob- (see OB-) + tenere, to hold: see TENANT]

obtect (äb tekt´) •adj. pertaining to an insect pupa in which the appendages and wings are glued down against the body by a secretion Also ob·tect´ed [< L obtectus, pp. of obtegere, to cover over < ob- (see OB-) + tegere, to cover: see THATCH, vt.]

obtest (äb test´) •vt. 1 to beg for; beseech; supplicate 2 to call to witness ob'tes·ta´tion (-tes tei´shэn) •n. [L obtestari < ob- (see OB-) + testari, to witness < testis, a witness: see TESTIFY]

obtrude (эb tru:d´, äb-) -trud´ed, -trud´ing •vt. 1 to thrust forward; push out; eject 2 to offer or force (oneself, one's opinions, etc.) upon others unasked or unwanted •vi. to obtrude oneself (on or upon) SYN. INTRUDE ob·trud´er •n. ob·tru´sion •n. [L obtrudere < ob- (see OB-) + trudere, to thrust: see THREAT]

obtrusive (эb tru:´siv, äb-) •adj. 1 inclined to obtrude 2 obtruding itself; esp., calling attention to itself in a displeasing way ob·tru´sive·ly •adv. ob·tru´sive·ness •n. [< L obtrusus, pp. of obtrudere + -IVE]

obtund (äb tûnd´) •vt. to make blunt or dull; make less acute; deaden [ME obtunden < L obtundere, to strike at, blunt < ob- (see OB-) + tundere, to strike < IE *(s)teud-, to strike > STOCK]

obturate (äb´tu: reit', -tyu:-) -rat'ed, -rat'ing •vt. [Rare] to close (an opening); stop up; obstruct ob'tu·ra´tion •n. ob´tu·ra'tor •n. [< L obturatus, pp. of obturare, to stop up < ob- (see OB-) + base akin to turgere, to swell: see TURGID]

obtuse (äb tu:s´, эb-; -tyu:s´) •adj. 1 not sharp or pointed; blunt 2 greater than 90 degrees and less than 180 degrees {an obtuse angle}: see ANGLE¹, illus. 3 slow to understand or perceive; dull or insensitive 4 not producing a sharp impression; not acute {an obtuse pain} SYN. DULL ob·tuse´ly •adv. ob·tuse´ness or ob·tu´si·ty •n. [L obtusus, blunted, dull, pp. of obtundere: see OBTUND]

obverse (for adj. äb vørs´, эb-; äb´vørs'; for n. äb´vørs') •adj. 1 turned toward the observer 2 narrower at the base than at the top {an obverse leaf} 3 forming a counterpart •n. 1 the side, as of a coin or medal, bearing the main design and the date: opposed to REVERSE 2 the front or main surface of anything 3 a counterpart 4 Logic the negative counterpart of an affirmative proposition, or the affirmative counterpart of a negative {no one is infallible is the obverse of everyone is fallible} ob·verse´ly •adv. [L obversus, pp. of obvertere, to turn toward < ob- (see OB-) + vertere, to turn: see VERSE]

obversion (äb vør´shэn, эb-; -zhэn) •n. 1 the act of obverting 2 Logic the act of inferring the obverse [LL obversio < L obversus: see OBVERSE]

obvert (äb vørt´, эb-) •vt. 1 to turn so that the main surface or a different surface is shown 2 Logic to state the obverse of (a proposition) [L obvertere: see OBVERSE]

obviate (äb´vi: eit') -at'ed, -at'ing •vt. to do away with or prevent by effective measures; make unnecessary ob'vi·a´tion •n. [< LL obviatus, pp. of obviare, to prevent < obvius: see OBVIOUS]

obvious (äb´vi: эs) •adj. 1 easy to see or understand; plain; evident 2 [Obs.] being in the way SYN. EVIDENT ob´vi·ous·ly •adv. ob´vi·ous·ness •n. [L obvius, in the way, lying open: see OB- & VIA]

obvolute (äb´vэ lu:t') •adj. having overlapping margins: said of leaves or petals: also ob´vo·lu'tive ob'vo·lu´tion •n. [L obvolutus, pp. of obvolvere, to wrap around < ob- (see OB-) + volvere, to roll: see WALK]

Obwalden (öp´väl'dэn) canton of central Switzerland: 189 sq. mi. (491 sq. km); pop. 26,000

OC 1 Officer Commanding 2 Old Catholic

oc- prefix OB-: used before c {occur}

Oc or oc ocean

ocarina (äk'э ri:´nэ) •n. a small, simple wind instrument shaped like a sweet potato, with finger holes and a mouthpiece: it produces soft, hollow tones [It, dim. of oca, a goose < LL auca, a goose (< *avica, back-form. < L avicula, dim. of avis, bird): from its fancied resemblance in shape]

O'Casey (ou kei´si:), Sean (shön) 1880-1964; Ir. playwright

Occam , William of see OCKHAM, William of

Occam's razor (äk´эmz) a philosophical or scientific principle according to which the best explanation of an event is the one that is the simplest, using the fewest assumptions or hypotheses Also sp. Ock´ham's razor [after prec., who used it often in analyzing problems]

occas 1 occasion 2 occasional 3 occasionally

occasion (э kei´zhэn; often ou kei´-) •n. 1 a favorable time or juncture; opportunity 2 a fact, event, or state of affairs that makes something else possible {a chance meeting was the occasion of the renewal of their friendship} 3 a) a happening; occurrence b) the time at which something happens; particular time {on the occasion of our last meeting} 4 a special time or event, suitable for celebration 5 need arising from circumstances 6 [pl.] a) [Obs.] needs; requirements b) [Archaic] affairs; business •vt. to be the occasion of; give occasion to; cause on occasion once in a while; sometimes; occasionally rise to the occasion to do whatever suddenly becomes necessary; meet an emergency take (the) occasion to use the opportunity (to do something) [ME occasioun < OFr < L occasio, accidental opportunity, fit time < occasus, pp. of occidere, to fall < ob- (see OB-) + cadere, to fall: see CASE¹]

occasional (э kei´zhэ nэl; often ou kÀ¿-) •adj. 1 occurring on a particular occasion 2 of or for a special occasion {occasional verse} 3 acting only on special occasions 4 of irregular occurrence; happening now and then; infrequent 5 designating chairs, tables, etc. intended for occasional or auxiliary use 6 being an OCCASION (n. 2)

occasionalism (-nэl iz'эm) •n. in post-Cartesian philosophy, the doctrine that, since mind and matter cannot interact, the intervention of God is required to synchronize corresponding acts of mind and movements of the body

occasionally (э kei´zhэn эl i:; often ou-) •adv. now and then; sometimes; on occasion

occident (äk´sэ dэnt, -dent') •n. [Old Poet.] the west [O-] the part of the world west of Asia, esp. Europe and the Americas [OFr < L occidens, direction of the setting sun < prp. of occidere, to fall: see OCCASION]

occidental (äk'sэ dent´ªl) •adj. 1 [Old Poet.] western 2 [O-] of the Occident, its people, or their culture; Western •n. [usually O-] a native of the Occident, or a member of a people native to that region [ME occidentale]

Occidentalism (äk'sэ dent´ªl iz'эm) •n. the character, culture, customs, etc. of the Occident Oc'ci·den´tal·ist •n.

Occidentalize (-aiz') -ized', -iz'ing •vt., vi. to make or become Occidental in character, culture, customs, etc.

occipital (äk sip´i tэl, -itªl) •adj. of the occiput or the occipital bone •n. OCCIPITAL BONE oc·cip´i·tal·ly •adv. [ML occipitalis]

occipital bone the bone that forms the back part of the skull: see SKULL, illus.

occiput (äk´si pût', -pэt) pl. oc·cip´i·ta (-sip´i tэ) •n.or -puts' the back part of the skull or head [ME < MFr < L < ob- (see OB-) + caput, HEAD]

occlude (э klu:d´, ä-) -clud´ed, -clud´ing •vt. 1 to close, shut, or block (a passage) 2 to prevent the passage of; shut in or out 3 to conceal, hide, or obscure 4 Chem. to retain or absorb (a gas, liquid, or solid) •vi. Dentistry to meet with the cusps fitting close together: said of the upper and lower teeth oc·clud´ent •adj. [L occludere < ob- (see OB-) + claudere, to CLOSE²]

occluded front Meteorol. the front formed when a warm front is overtaken by a cold front and an air mass is forced aloft up the warm-front or cold-front surface

occlusion (э klu:´zhэn) •n. 1 an occluding or being occluded 2 Dentistry the fitting together of the upper and lower teeth, or the way in which these fit together when the jaws are closed 3 Meteorol. OCCLUDED FRONT 4 Phonet. the complete closing of the air passages in pronunciation, as of a stop oc·clu´sive •adj.

occult (for adj. э kûlt´; also ä´kûlt'; for v. э kûlt´) •adj. 1 hidden; concealed 2 secret; esoteric 3 beyond human understanding; mysterious 4 designating or of certain alleged mystic arts, such as magic, alchemy, astrology, etc. •vt., vi. 1 to hide or become hidden from view 2 Astron. to hide by occultation the occult the occult arts or studies oc·cult´ly •adv. oc·cult´ness •n. [L occultus, concealed, pp. of occulere, to cover over < ob- (see OB-) + celare, to hide (see HALL)]

occultation (äk'ûl tei´shэn) •n. 1 the state of becoming hidden or of disappearing from view 2 Astron. the disappearance of a celestial body behind a closer, apparently larger celestial body, as when a star or planet is hidden by the moon [ME occultacioun < L occultatio, a hiding < occultus: see OCCULT]

occulting light an intermittent light in a lighthouse, lightship, etc., characterized by a period of light that equals or exceeds the period of darkness

occultism (э kûlt´iz'эm) •n. 1 belief in occult forces and powers 2 preoccupation with occult arts oc·cult´ist •n.

occupancy (äk´yu: pэn si:, -yэ-) pl. -cies •n. 1 a) an occupying; a taking or keeping in possession b) the period during which a house, etc. is occupied 2 the condition of being occupied 3 Law the taking possession of a previously unowned object, thus establishing ownership [< fol.]

occupant (äk´yu: pэnt, -yэ-) •n. 1 a person who occupies a house, post, etc. 2 a person who acquires title to anything by occupancy [< L occupans, prp. of occupare, OCCUPY]

occupation (äk'yu: pei´shэn, -yэ-) •n. 1 an occupying or being occupied; specif., the seizure and control of a country or area by military forces 2 that which chiefly engages one's time; (one's) trade, profession, or business oc'cu·pa´tion·al •adj. oc'cu·pa´tion·al·ly •adv. [OFr < L occupatio]

occupational disease a disease commonly acquired by people in a particular occupation, as silicosis among miners

occupational therapy therapy by means of work, as arts and crafts, designed to divert the mind, to correct a particular physical defect, or to equip a handicapped patient with new job skills

occupy (äk´yu: pai', -yэ-) -pied', -py'ing •vt. 1 to take possession of by settlement or seizure 2 to hold possession of by tenure; specif., a) to dwell in b) to hold (a position or office) 3 to take up or fill up (space, time, etc.) 4 to employ, busy, or engage (oneself, one's attention, mind, etc.) oc´cu·pi'er •n. [ME occupien < OFr occuper < L occupare, to take possession of, possess < ob- (see OB-) + capere, to seize: see HAVE]

occur (э kør´) -curred´, -cur´ring •vi. 1 to be found; exist {fish occur in most waters} 2 to present itself; come to mind {an idea occurred to him} 3 to take place; happen SYN. HAPPEN [L occurrere, to run, come up to, meet < ob- (see OB-) + currere, to run: see CURRENT]

occurrence (э kør´эns) •n. 1 the act or fact of occurring 2 something that occurs; event; incident oc·cur´rent •adj. SYN.—occurrence is the general word for anything that happens or takes place [an unforeseen occurrence]; an event is an occurrence of relative significance, especially one growing out of earlier happenings or conditions [the events that followed the surrender]; an incident is an occurrence of relatively minor significance, often one connected with a more important event [the award was just another incident in his career]; an episode is a distinct event that is complete in itself but forms part of a larger event or is one of a series of events [an episode of his childhood]; a circumstance is an event that is either incidental to, or a determining factor of, another event [the circumstances surrounding my decision]

OCD Office of Civil Defense

ocean (ou´shэn) •n. 1 the great body of salt water that covers approximately 71% of the surface of the earth 2 any of its four principal geographical divisions: the Atlantic, Pacific, Indian, or Arctic Ocean 3 any great expanse or quantity [ME occean < OFr < L Oceanus < Gr Ōkeanos, the outer sea (in contrast to the Mediterranean), orig. thought of as a great river flowing around the earth]

ocean sunfish any of a family (Molidae, order Tetraodontiformes) of marine bony fishes with an abruptly truncated body; esp., any of a large, sluggish species (Mola mola)

oceanarium (ou'shэ ner´i: эm) pl. -i·ums or -i·a (ou'shэ ner´i: э) •n. a large salt-water aquarium for ocean fish and animals [prec. + (AQU)ARIUM]

oceanaut (ou´shэ nöt') •n. AQUANAUT [< OCEAN + (AQUA)NAUT]

oceangoing (ou´shэn gou'iŋ) •adj. of, or made for, travel on the ocean

Oceania (ou'shi: æn´i: э) islands in the Pacific, including Melanesia, Micronesia, & Polynesia (incl. New Zealand) &, sometimes, Australia & the Malay Archipelago: also O'ce·an´i·ca (-i kэ) O'ce·an´i·an •adj., n.

oceanic (ou'shi: æn´ik) •adj. 1 of, living in, or produced by the ocean 2 like the ocean; vast 3 designating or of the ecological zone (oceanic zone) beyond the neritic zone in the ocean

Oceanid (ou si:´э nid') pl. O'ce·an´i·des' (-æn´i di:z') •n. Gr. Myth. any of three thousand ocean nymphs, daughters of Oceanus and Tethys [Gr Ōkeanis (gen. Ōkeanidos)]

oceanography (ou'shэ näg´rэ fi:, ou'shi: э-) •n. the study of the environment in the oceans, including the waters, depths, beds, animals, plants, etc. o'ce·an·og´ra·pher •n. o'ce·an·o'graph´ic (-nou'græf´ik) or o'ce·an·o·graph´i·cal •adj. [< Ger oceanographie < Fr océanographie: see OCEAN & -GRAPHY]

oceanology (-näl´э ji:) •n. 1 the study of the sea in all its aspects, including oceanography, geophysical phenomena, undersea exploration, economic and military uses, etc. 2 OCEANOGRAPHY o'ce·an·ol´o·gist •n. [OCEAN + -O- + -LOGY]

Oceanside (ou´shэn said') city in SW Calif., near San Diego: pop. 128,000 [descriptive]

Oceanus (ou si:´э nэs) Gr. Myth. 1 a Titan, father of the Oceanides and ruler of the sea before Poseidon 2 the great outer stream supposedly encircling the earth [L < Gr Ōkeanos: see OCEAN]

ocellate (äs´э leit'; ou sel´it, -eit') •adj. 1 resembling an ocellus 2 having an ocellus or ocelli 3 spotted Also, for OCELLATE senses 2 & 3, oc´el·lat'ed

ocellation (äs'э lei´shэn) •n. an eyelike spot

ocellus (ou sel´эs) pl. -li' (-ai') •n. 1 the simple eyespot of certain invertebrates, as distinguished from the compound eye of an insect or the camera-type eye of vertebrates and cephalopods 2 an eyelike spot, as on a peacock's feathers o·cel´lar •adj. [L, dim. of oculus, EYE]

ocelot (äs´э lэt, -lät'; also, ou´sэ-) pl. -lots •n.or -lot any of various wild, spotted cats of North and South America; esp., a large species (Leopardus pardalis) with a yellow or gray coat marked with black spots [Fr, use (by BUFFON) of Nahuatl o:se:lo:λ, jaguar]

OCelt Old Celtic

ocher (ou´kэr) •n. 1 an earthy clay colored by iron oxide, usually yellow or reddish brown: used as a pigment in paints 2 the color of ocher; esp., dark yellow o´cher·ous •adj. [ME ocra < L ochra < Gr ōchra < ōchros, pale, pale-yellow]

ochlocracy (äk läk´rэ si:) •n. government by the mob; mob rule och·lo·crat (äk´lou kræt') •n. och'lo·crat´ic •adj. [Fr ochlocratie < Gr ochlokratia < ochlos, a mob, populace + -kratia, -CRACY]

Ochoa (ou chou´э), Se·ve·ro (sэ ver´ou) 1905- ; U.S. biochemist, born in Spain

ochone (э khoun´) •interj. [Scot. or Irish] alas! woe!

ochre (ou´kэr) o´chred, o´chring •n., vt. alt. sp. of OCHER o´chre·ous (-kэr эs, -kri: эs) •adj.

ochroid (ou´kroid') •adj. resembling ocher; of a dark-yellow color [Gr ōchroeidēs: see OCHER & -OID]

Ochs (äks), Adolph Simon 1858-1935; U.S. newspaper publisher

-ock (эk) [Archaic] suffix little (specified thing) {hillock} It has lost its meaning as a diminutive in some words, as buttock, ruddock [ME -ok < OE -oc, -uc, dim.]

ocker (äk´эr) •n. [also O-] [Austral. Slang] a rough or boorish person

Ockham (äk´эm), William of c. 1285-c. 1349; Eng. philosopher

o'clock (э kläk´, ou-) •adv. 1 of or according to the clock {nine o'clock at night} 2 as if on a clock dial, with the number 12 straight ahead or directly overhead: used to indicate direction, esp. of an approaching aircraft

O'Connell (ou kän´ªl), Daniel 1775-1847; Ir. nationalist leader

O'Connor (ou kän´эr) 1 (Mary) Flan·ner·y (flæn´nэ ri:) 1925-64; U.S. writer 2 Frank (born Michael John O'Donovan) 1903-66; Ir. author 3 Sandra Day 1930- ; associate justice, U.S. Supreme Court (1981- ) 4 Thomas Power 1848-1929; Ir. journalist & nationalist leader: called Tay Pay

ocotillo (ou'kэ ti:´you) pl. -los (-youz) •n. a spiny, desert candlewood (Fouquieria splendens) with scarlet flowers, found in the SW U.S. •adj. designating a family (Fouquieriaceae, order Violales) of dicotyledonous desert shrubs and trees, including the candlewoods [AmSp, dim. of ocote, Mexican pine < Nahuatl ocoλ, pine]

OCR (ou si: är´) •n. 1 optical character recognition: electronic identification of alphanumeric characters, esp. those typewritten or printed on paper, for computer processing or storage 2 a device that performs optical character recognition

ocrea (äk´ri: э, ou´kri: э) pl. -re·ae' (-i:) •n. Bot. a tubelike covering around some stems, formed of the united stipules: found esp. in the buckwheat family oc´re·ate (-it, -eit') •adj. [ModL < L, a legging, greave < Gr okris, a projection, peak, edge < IE *okri- < base *a-, *o-, sharp > ACID]

OCS Officer Candidate School

OCSO Order of Cistercians of the Strict Observance (Trappists)

Oct October oct octavo

oct- (äkt) combining form 1 OCTA- 2 OCTO- Used before a vowel

octa- (äk´tэ) combining form eight {octagon} [Gr okta- < oktō, EIGHT]

octachord (äk´tэ kôrd') •n. Music 1 an octave of the diatonic scale 2 any eight-stringed musical instrument [L octachordus < Gr oktachordos, eight-stringed: see OCTA- & CHORD¹]

octad (äk´tæd') •n. 1 a series or group of eight 2 Chem. an element, atom, or radical with a valence of eight [Gr oktas (gen. oktados) < oktō, EIGHT]

octagon (äk´tэ gän') •n. a plane figure with eight angles and eight sides oc·tag´o·nal (-tæg´э nэl) •adj. oc·tag´o·nal·ly •adv. [L octagonum < Gr oktagōnos, eight-cornered: see OCTA- & -GON]

octahedrite (äk'tэ hi:´drait') •n. a tetragonal mineral, titanium dioxide, TiO2 [< LL octaedros (< Gr oktaedros: see OCTAHEDRON) + -ITE¹: orig. thought to crystallize in octahedrons]

octahedron (äk'tэ hi:´drэn) pl. -drons or -dra (-drэ) •n. a solid figure with eight plane surfaces: see POLYHEDRON, illus. oc'ta·he´dral •adj. [Gr oktaedron, neut. of oktaedros: see OCTA- & -HEDRON]

octal (äk´tэl) •adj. 1 of or based on the number eight 2 designating an electronic tube base or its matching socket designed to hold eight equally spaced pins [OCT- + -AL]

octamerous (äk tæm´эr эs) •adj. having eight parts in each whorl: said of flowers Also written 8-merous [OCTA- + -MEROUS]

octameter (äk tæm´эt эr) •n. a line of verse containing eight metrical feet or measures [LL, having eight feet < Gr oktametros: see OCTA- & METER¹]

octan (äk´tэn) •adj. occurring every eighth day (counting both days of occurrence) •n. an octan fever, etc. [< L octo, EIGHT + -AN]

octane (äk´tein') •n. an oily alkane, C8H18, occurring in petroleum, or any of a group of isomers of this substance [OCT- + -ANE]

octane number (or rating) a number representing the antiknock properties of a gasoline, fuel mixture, etc., determined by the percentage of isooctane that must be mixed with normal heptane to produce the knocking quality of the fuel being tested: the higher the number, the greater the antiknock properties

octanoic acid (äk'tэ nou´ik) CAPRYLIC ACID

octanol (äk´tэ nôl', -noul') •n. any of four colorless, liquid alcohols, C8H17OH, used in perfumery and as solvents, foam-control agents, etc. [OCTAN(E) + -OL¹]

Octans (äk´tænz) a S constellation containing the celestial pole [ModL: see OCTANT]

octant (äk´tэnt) •n. 1 an eighth of a circle; 45° angle or arc 2 an instrument like the sextant, for measuring angles 3 Astron. the position of one celestial body when it is 45° distant from another 4 Math. any of the eight parts into which a space is divided by three planes intersecting at a single point and at right angles to one another [LL octans, eighth part < L octo, EIGHT]

octave (äk´tiv; also, -teiv') •n. 1 a) the eighth day following a church festival, counting the festival day as the first b) the entire period between the festival and this day 2 a group of eight lines of verse; specif., the first eight lines of a Petrarchan sonnet 3 any group of eight 4 Fencing a position of thrust or parry in which the hand is rotated with the palm up 5 Music a) the eighth tone of an ascending or descending diatonic scale, or a tone seven degrees above or below a given tone in such a scale b) the interval of seven diatonic degrees between a tone and either of its octaves c) the series of tones contained within this interval, or the keys of an instrument producing such a series d) a tone and either of its octaves sounded together e) an organ stop producing tones an octave above those ordinarily produced by the keys struck •adj. 1 consisting of eight, or an octave 2 Music producing tones an octave higher {an octave key} oc·ta·val (äk tei´vэl, eik´tэ vэl) •adj. [OFr < L octava, fem. of octavus, eighth < octo, EIGHT]

Octavia (äk tei´vi: э) 1 a feminine name: see OCTAVIUS 2 died 11 B.C.; wife of Mark Antony [L, fem. of Octavius]

Octavian (-эn) see AUGUSTUS (the emperor)

Octavius (-эs) a masculine name: fem. Octavia [L < octavus, eighth]

octavo (äk tei´vou, -tä´-) pl. -vos •n. 1 the page size of a book made up of printer's sheets folded into eight leaves: the usual size of each leaf is 6 by 9 inches 2 a book consisting of pages of this size Also called eightvo and written 8vo or 8° •adj. consisting of pages of this size [< L (in) octavo, (in) eight, abl. of octavus: see OCTAVE]

octennial (äk ten´i: эl) •adj. 1 happening every eight years 2 lasting eight years oc·ten´ni·al·ly •adv. [< LL octennium, period of eight years (< L octo, eight + annus, year) + -AL]

octet or octette (äk tet´) •n. 1 any group of eight; esp., an OCTAVE (sense 2) 2 Music a) a composition for eight voices or eight instruments b) the eight performers of this [OCT- + (DU)ET]

octillion (äk til´yэn) •n. Æ 1 the number represented by 1 followed by 27 zeros 2 [Brit.] the number represented by 1 followed by 48 zeros •adj. amounting to one octillion in number [Fr < L octo, EIGHT + Fr (m)illion]

octo- (äk´tou, -tэ) combining form eight {octopus} [Gr oktō- < oktō, EIGHT]

October (äk tou´bэr) •n. 1 the tenth month of the year, having 31 days: abbrev. Oct or O 2 [Brit.] ale brewed in October [ME < OE < L < octo, EIGHT (+ -ber < ?): so named as the eighth month of the ancient Roman year, which began with March]

October Revolution see RUSSIAN REVOLUTION

octodecimo (äk'tou des´э mou') pl. -mos' •n. 1 a page size (about 4 by 6½ in.), ¹/18 of a printer's sheet 2 a book with pages of this size Also called eighteenmo, and written 18mo or 18° •adj. with pages of this size [< L (in) octodecimo, (in) eighteen, abl. of octodecimus, eighteenth]

octogenarian (äk'tou ji ner´i: эn, -tэ-) •adj. 80 years old, or between the ages of 80 and 90 •n. a person of this age [L octogenarius, containing eighty < octogeni, eighty each < octoginta, eighty: see OCTO- & -TY²]

octonary (äk´tэ ner'i:) •adj. of or consisting of eight or groups of eight •n. pl. -nar'ies 1 a group of eight 2 a stanza of eight lines [L octonarius < octo, EIGHT]

octopod (äk´tэ päd') •n. any animal with eight limbs; specif., any of an order (Octopoda) of cephalopod mollusks, including the octopus and the paper nautilus oc·top´o·dan (-täp´э dэn) •adj., n. oc·top´o·dous (-dэs) •adj. [< Gr oktōpous (gen. octōpodos): see OCTOPUS]

octopus (äk´tэ pэs) pl. -pus·es, -pi' (-pai'), or oc·top·o·des (äk täp´э di:z') •n. 1 any of various octopods (order Octopoda) having a soft, saclike body, a reduced coelom, an internal vestigial shell, and eight sucker-bearing arms around the mouth 2 anything suggesting an octopus; esp., an organization with branches that reach out in a powerful and influential manner [ModL < Gr oktōpous, eight-footed < oktō, EIGHT + pous (gen. podos), FOOT]

octoroon (äk'tэ ru:n´) •n. a person who has one black great-grandparent; child of a quadroon and a white [OCTO- + (QUAD)ROON]

octosyllabic (äk'tou si læb´ik, -tэ-) •adj. 1 containing eight syllables, as a line of verse 2 containing lines of eight syllables

octosyllable (äk´tou sil'э bэl, -tэ-) •n. a word or a line of verse having eight syllables •adj. OCTOSYLLABIC

octroi (äk´troi'; Fr ôk třwå´) pl. -trois' (-troiz'; Fr, -třwå´) •n. 1 a tax on certain goods entering a town 2 the place where this tax is collected 3 the official or officials collecting this tax [Fr < octroyer, for earlier ottroyer, otreier, to grant < VL *auctoricare < L auctor: see AUTHOR]

octuple (äk´tэ pэl, äk tu:´pэl) •adj. 1 eightfold 2 consisting of eight parts •n. something eight times as great as something else •vt. -pled, -pling to multiply by eight [L octuplus < octo, EIGHT + -plus: see DOUBLE]

ocular (äk´yu: lэr, -yэ-) •adj. 1 of, for, or like the eye 2 by eyesight {an ocular demonstration} •n. the lens or lenses constituting the eyepiece of an optical instrument oc´u·lar·ly •adv. [LL ocularis < L oculus, EYE]

oculist (äk´yu: list, -yэ-) •n. early term for OPHTHALMOLOGIST [Fr oculiste < L oculus, EYE]

oculo- (äk´yu: lou, -lэ; -yэ-) combining form eye, eye and {oculomotor} [< L oculus, EYE]

oculomotor (äk'yu: lou mout´эr, -yэ-) •adj. moving the eyeball; specif. designating or of either nerve of the third pair of cranial nerves, arising in the midbrain and supplying four of the six muscles that move each eyeball [prec. + MOTOR]

od (äd) pl. od •n. a hypothesized force in nature formerly thought to manifest itself in such phenomena as hypnotism, magnetism, light, etc. od´ic •adj. [Ger, coined by K. v. Reichenbach (1788-1869), Ger scientist] OD abbrev. 1 Doctor of Optometry: also O.D. [L] 2 Officer of the Day 3 olive drab 4 outside diameter Also, for 3 & 4, od OD (ou´di:´) pl. ODs •n.or OD's [Slang] an overdose, esp. of a narcotic •vi. OD'd or ODed, OD'ing or ODing [Slang] to take an overdose, esp. a fatal overdose of a narcotic

Od or 'Od (äd) •interj. [often o-] [Archaic] an expression of surprise, etc. [euphemism for God]

odalisque or odalisk (ou´dэ lisk', oud´ªl isk') •n. 1 a female slave or concubine in an Oriental harem 2 a conventionalized painting of a reclining odalisque as by Ingres or Matisse [Fr odalisque < Turk ōdalik, chambermaid < ōdah, chamber + -lik, suffix expressing function]

ODan Old Danish

Odd (äd) •interj. alt. sp. of OD odd (äd) •adj. 1 a) being one of a pair of which the other is missing {an odd glove} b) being the one remaining after the others are paired, grouped, taken, etc. c) being one or more of a set, series, or group separated from the others {a few odd volumes of Dickens} 2 having a remainder of one when divided by two; not even: said of numbers 3 numbered with an odd number {the odd months} 4 a) in addition to that mentioned in a round number {ten dollars and some odd change} b) with a relatively small number over that specified (usually in hyphenated compounds) {twenty-odd children} 5 not the usual, regular, habitual, accounted for, etc.; occasional; incidental {odd jobs, at odd moments} 6 a) not usual or ordinary; singular; peculiar; strange b) queer; eccentric 7 out-of-the-way {in odd corners} SYN. STRANGE odd´ly •adv. odd´ness •n. [ME odde < ON oddi, point of land, triangle, hence (from the third angle) odd number, akin to OE ord, a point < Gmc *uzda- (> Ger ort, place, orig., point) < IE *uds (< base *ud-, up > OUT) + *dho-, var. of *dhē, to place, put > DO¹]

Odd Fellow a member of the Independent Order of Odd Fellows, a fraternal and benevolent secret society founded in England in the 18th cent.

odd lot an amount smaller than the usual unit of trading; specif., a quantity of less than 100 shares of stock in a transaction odd-lot (äd´lät´) •adj.

odd man out 1 a) a method, as in a game, for singling out one person from a group, as by matching coins b) the person thus singled out 2 any atypical or unconventional person or thing

oddball (äd´böl') •n. [Slang] an eccentric, unconventional, or nonconforming person •adj. [Slang] strange or unconventional [ODD + BALL¹]

oddity (äd´э ti:) •n. 1 the state or quality of being odd; queerness; peculiarity; strangeness 2 pl. -ties an odd person or thing

oddment (äd´mэnt) •n. 1 any of various miscellaneous items 2 a scrap or remnant [ODD + -MENT]

odd-pinnate (äd´pin´eit) •adj. Bot. pinnate with an odd, or single, terminal leaflet: see LEAF, illus.

odds (ädz) •n.pl. [sometimes, esp. formerly, with sing. v.] 1 [Archaic] inequalities 2 [Now Rare] difference or amount of difference 3 difference in favor of one side over the other; advantage 4 an equalizing advantage given or received in betting, based on a given bettor's assumed chance of winning and expressed as a ratio {a winning bettor who got odds of 3 to 1 is paid three times as much as he or she bet} at odds in disagreement; quarreling by (all) odds by far; unquestionably (the) odds are the likelihood is

odds and ends scraps; remnants; oddments

oddsmaker (ädz´meik'эr) •n. a person, usually an expert, who estimates the odds, or advantage, in betting or competing

odds-on (ädz´än´) •adj. having better, often much better, than an even chance of winning {an odds-on favorite}

ode (oud) •n. 1 orig., a poem written to be sung 2 in modern use, a lyric poem, rhymed or unrhymed, typically addressed to some person or thing and usually characterized by lofty feeling, elaborate form, and dignified style od·ic (oud´ik) •adj. [Fr < LL oda < Gr ōidē, song, contr. < aoidē < aeidein, to sing < IE *aweid- < base *aw-, to speak > Sans vádati, (he) speaks]

-ode¹ (oud) suffix way, path {electrode} [< Gr hodos, path, way < IE base *sed-, to go > L cedere]

-ode² (oud) suffix something that resembles (a specified thing) {phyllode, nematode} [Gr -ōdēs, ōdes < -ō-, ending of base or thematic vowel + -eidēs, like, -OID]

Odense (ou´θэn sэ, -dэn-) seaport on N Fyn island, Denmark: pop. 171,000

Oder (ou´dэr) river in central Europe, flowing north through Czech Republic & Poland into the Baltic: c. 560 mi. (900 km): it forms, with the Neisse, the boundary (Oder-Neisse Line) between Germany & Poland

Odessa (ou des´э; Russ ô de´sä) 1 seaport in S Ukraine, on the Black Sea: pop. 1,126,000 2 city in WC Tex.: pop. 90,000 [after the Ukrainian city]

Odets (ou dets´), Clifford 1906-63; U.S. playwright

odeum (ou di:´эm) pl. o·de´ums or o·de´a (-э) •n. 1 in ancient Greece and Rome, a roofed building for musical performances 2 a modern concert hall [LL < Gr ōideion < ōidē: see ODE]

Odin (ou´din) Norse Myth. the chief deity, god of art, culture, war, and the dead: identified with the Germanic Woden [Dan < ON Othinn, akin to OE Woden]

odious (ou´di: эs) •adj. arousing or deserving hatred or loathing; disgusting; offensive SYN. HATEFUL o´di·ous·ly •adv. o´di·ous·ness •n. [OFr odieus < L odiosus < odium, hatred: see ODIUM]

odium (ou´di: эm) •n. 1 a) hatred, esp. of a person or thing regarded as loathsome b) the state or fact of being hated 2 the disgrace brought on by hateful action; opprobrium [L, hatred, ill will < odi, I hate < IE base *od-, hatred > Gr odyssasthai, to be angry, ON atall, frightful]

Odoacer (ou'dou ei´sэr) c. A.D. 435-493; 1st barbarian ruler of Italy (476-493)

odograph (ou´dэ græf') •n. a device for measuring distance traveled [< Gr hodos, way (see -ODE¹) + -GRAPH]

odometer (ou däm´эt эr) •n. an instrument for measuring the distance traveled by a vehicle [Fr odomètre < Gr hodometros < hodos, way (see -ODE¹) + metron, MEASURE]

-odont (ou dänt´, э-) combining form 1 forming adjectives having teeth of a (specified) type {pleurodont} 2 forming nouns an animal having teeth of a (specified) type [see ODONTO-]

odonto- (ou dän´tou, -tэ) combining form tooth or teeth {odontoblast, odontology} Also, before a vowel, odont- [< Gr odōn, odous (gen. odontos), TOOTH]

odontoblast (ou dänt´ou blæst') •n. any of the cells forming the outer surface of the pulp of a tooth and secreting a substance which develops into dentin o·don'to·blas´tic •adj. [prec. + -BLAST]

odontoglossum (ou dänt'ou gläs´эm) •n. any of a genus (Odontoglossum) of tropical American, epiphytic orchids with clustered flowers of various colors [ModL < ODONTO- + Gr glōssa, a tongue: see GLOSS²]

odontoid (ou dän´toid') •adj. 1 toothlike 2 designating or of a toothlike or peg-shaped process projecting from the second vertebra of the neck, on which the top vertebra moves and rotates [Gr odontoeidēs: see ODONTO- & -OID]

odontology (ou'dän täl´э ji:) •n. the science dealing with the structure, growth, and diseases of the teeth; dentistry o·don'to·log´i·cal (-tou läj´i kэl) •adj. o·don'to·log´i·cal·ly •adv. o'don·tol´o·gist •n. [Fr odontologie: see ODONTO- & -LOGY]

odontophore (ou dän´tэ för') •n. a muscular structure of most mollusks, usually protrusile, supporting the radula o'don·toph´o·ral (-täf´э rэl) •adj. [ODONTO- + -PHORE]

odor (ou´dэr) •n. 1 a) that characteristic of a substance which makes it perceptible to the sense of smell b) a smell, whether pleasant or unpleasant; fragrance, stench, etc. 2 a pervasive atmosphere or quality {an odor of intolerance} 3 [Archaic] a perfume or other sweet-smelling substance SYN. SMELL be in bad (or ill) odor to be in ill repute o´dor·less •adj. [OFr < L < IE base *od-, to smell, odor > Gr odmē, (var. of osmē), scent, Swed os, smell, suffocating gas]

odorant (ou´dэr эnt) •n. any substance or thing that produces a perceptible odor [prec. + -ANT]

odoriferous (ou'dэr if´эr эs) •adj. giving off an odor, now often, specif., a strong or offensive one o'dor·if´er·ous·ly •adv. [ME < L odorifer: see ODOR & -FEROUS]

odorous (ou´dэr эs) •adj. having a pronounced odor o´dor·ous·ly •adv. o´dor·ous·ness •n.

odour (ou´dэr) •n. Brit., etc. sp. of ODOR

Odovacar (ou'dou vei´kэr) var. of ODOACER

Odra (ô´dřä) Pol. name of ODER

ODu Old Dutch

-odus (э dэs) combining form an animal having (a specified kind of) teeth {ceratodus} [ModL < Gr -odous < odōn, TOOTH]

-odynia (э din´i: э, -dain´-) combining form pain in (a specified organ or part) [ModL < Gr -odynia < odynē, a pain < IE *od-, var. of base *ed-, to EAT]

Odysseus (ou dis´i: эs, ou dis´yu:s') the hero of the Odyssey, a king of Ithaca and one of the Greek leaders in the Trojan War: Latin name Ulysses [Gr]

Odyssey (äd´i si:) an ancient Greek epic poem, ascribed to Homer, about the wanderings of Odysseus during the ten years after the fall of Troy •n. pl. -seys [o-] any extended wandering or journey Od'ys·se´an •adj. [L Odyssea < Gr Odysseia]

Oe oersted OE Old English oe (ou) •n. a whirlwind near the Faeroe Islands [< Faeroese othi < othur, raging < ON other] oe abbrev. omissions excepted

oe- an earlier variant spelling for many words of Greek and Latin origin now usually written with initial e-