A- (3) prefix meaning "not," from Gk a-, an- "not," from pie base *ne "not" (see un-)

opponent --- 1588, from L. opponentem (nom. opponens), prp. of opponere "oppose, object to, set against," from ob "against" + ponere "to put, set, place" (see position).

opportune --- c.1408, from L. opportunus "favorable," from the phrase ob portum veniens "coming toward a port," in reference to the wind, from ob "to, toward" + portus "harbor." Opportunist (1881) and opportunism (1870) both borrowed from It. opportunismo, a word in It. politics, later applied in Fr. to Gambetta (1881) and then generally in Eng. to any who seek to profit from the prevailing circumstances.

opportunity --- 1375, from O.Fr. opportunite (13c.), from L. opportunitatem (nom. opportunitas) "fitness, suitableness, favorable time," from opportunus (see opportune).

oppose --- c.1386, from O.Fr. opposer, from O.Fr. poser "to place, lay down" (see pose), blended with L. opponere "oppose, object to, set against" (see opponent). Opposable in ref. to thumbs is from 1833.

opposite --- 1391, "placed on the other side of (something)," from O.Fr. oposite (13c.), from L. oppositus, pp. of opponere "set against" (see opponent). Meaning "contrary in nature or character" is from 1580.

opposition --- c.1386, an astrological term for two heavenly bodies exactly across from one another in the sky, from O.Fr. oposicion (12c.), from L. oppositionem (nom. oppositio) "act of opposing," from pp. stem of opponere "set against" (see opponent). Meaning "contrast, antagonism" first attested 1581; sense of "political party opposed to the one in power" is from 1704.

oppress --- c.1340, from O.Fr. oppresser (13c.), from M.L. oppressare, freq. of L. opprimere "press against, crush" (in L.L. "to rape"), from ob "against" + premere "to press, push" (see press (v.1)). Oppression (1340) "harsh exercise of authority" is from O.Fr. opression, from L. oppressionem (nom. oppressio), from pp. stem of opprimere.

opprobrious --- full of reproach, intended to bring disgrace, 1387, from O.Fr. opprobrieux, from L.L. opprobriosus, from L. opprobare "to reproach, taunt," from ob "against" + probrum "reproach, infamy." Etymological sense is "disgrace attached to conduct considered shameful." Opprobrium "cause of reproach, something that brings disgrace," is attested from 1656.

opry --- 1914, U.S. dial. pronunciation of opera. Esp. in Grand Ole Opry, a radio broadcast of country music from Nashville, registered as a proprietary name 1950.

opsimathy --- 1656, from Gk. opsimathia "learning late in life," from opse "late" (related to opiso "backward" + opisthen "behind") + manthanein "to learn."

opt --- 1877, from Fr. opter "to choose," from L. optare "choose, desire" (see option). To opt out is attested from 1922.

optative --- grammatical mood expressing wish or desire, 1530, from M.Fr. optatif (15c.), from L.L. optativus, from L. optatus, pp. of optare (see option).

optic --- 1541, from M.Fr. optique, obtique (c.1300), from M.L. opticus "of sight or seeing," from Gk. optikos "of or having to do with sight," from optos "seen, visible," from op-, root of opsesthai "be going to see," related to ops "eye," from PIE *oqw- "eye/see" (see eye). Optics "science of sight and light" is from 1579; optician is first attested 1687, after Fr. opticien.

optimal --- most favorable, 1890, from L. optimus (see optimum). Originally a word in biology.

optimism --- 1782, from Fr. optimisme (1737), from Mod.L. optimum, used by Leibnitz (in Théodicée, 1710) to mean "the greatest good," from L. optimus "the best" (see optimum). The doctrine holds that the actual world is the "best of all possible worlds," in which the creator accomplishes the most good at the cost of the least evil.

optimize --- 1844, "to act as an optimist," back-formation from optimist. Meaning "to make the most of" is first recorded 1857.

optimum --- 1879, from L. optimum, neut. sing. of optimus "best" (used as a superl. of bonus "good"), probably related to ops "power, resources" (in which case the evolution is from "richest" to "the most esteemed") or to ob "in front of," with superlative suffix *-tumos. Originally in biology, in ref. to "conditions most favorable" (for growth, etc.).

option --- 1604, "action of choosing," from Fr. option, from L. optionem (nom. optio) "choice, free choice," related to optare "to desire, choose," from PIE base *op- "to choose, prefer." Meaning "thing that may be chosen" is attested from 1885. Commercial transaction sense first recorded 1755 (the verb in this sense is from 1934). As a N.Amer. football play, it is recorded from 1954. Optional, in ref. to things which may be done or not done, is from 1792.

optometry --- 1886, from optometer (1738), an instrument for testing vision, from opto- "sight," from Gk. optos "seen, visible" + Gk. metron "measure" (see meter (2)). Probably influenced by Fr. optométrie.

opulence --- c.1510, from M.Fr. opulence, from L. opulentia, from opulentus "wealthy," dissimilated from *op-en-ent-, related to ops "wealth, power, resources," opus "work, labor, exertion," from PIE base *op- "to work, produce in abundance" (see opus).

opus --- 1809, "a work, composition," esp. a musical one," from L. opus "a work, labor, exertion" (cf. It. opera, Fr. oeuvre, Sp. obra), from PIE base *op- (Gmc. *ob-) "to work, produce in abundance," originally of agriculture later extended to religious acts (cf. Skt. apas- "work, religious act;" Avestan hvapah- "good deed;" O.H.G. uoben "to start work, to practice, to honor;" Ger. üben "to exercise, practice;" Du. oefenen, O.N. æfa, Dan. øve "to exercise, practice;" O.E. æfnan "to perform, work, do," afol "power"). The plural, seldom used, is opera.

-or --- suffix forming nouns of quality, state, or condition, from M.E. -our, from O.Fr. -our (Fr. -eur), from L. -orem (nom. -or), a suffix added to pp. verbal stems. Also in some cases from L. -atorem (nom. -ator). The -our form predominated after c.1300, but there was a partial revival of -or on the L. model from 16c. In U.S., via Webster, -or is universal, while in Britain -our is used in most cases (but with exceptions: author, error, senator, ancestor, etc.).

or --- c.1200, from O.E. conj. oþþe "either, or," related to O.N. eða, O.H.G. odar, Ger. oder, Goth. aiþþau "or." This was extended in early M.E. with an -r ending, perhaps by analogy of other "choice between alternative" words that ended this way (either, whether), then reduced to oþþr, at first in unstressed situations (commonly thus in Northern and Midlands Eng. by 1300), and finally reduced to or, though other survived in this sense until 16c. The contraction took place in the second term of an alternative, such as either ... or, a common construction in O.E., where both words originally were oþþe (see nor).

oracle --- c.1384, "a message from a god, expressed by divine inspiration," from O.Fr. oracle (12c.), from L. oraculum "divine announcement, oracle," from orare "pray, plead" (see orator), with material instrumental suffix -culo-. In antiquity, "the agency or medium of a god," also "the place where such divine utterances were given." This sense is attested in Eng. from c.1400.

oral --- 1625, from L.L. oralis, from L. os (gen. oris) "mouth, opening, face, entrance," from PIE *os-/*ous- "mouth" (cf. Skt. asan "mouth," asyam "mouth, opening," Avestan ah-, Hittite aish, M.Ir. a "mouth," O.N. oss "mouth of a river," O.E. or "beginning, origin, front"). Psychological meaning "of the mouth as the focus of infantile sexual energy" (e.g. oral fixation) is from 1910. The sexual sense is first recorded 1948, in Kinsey.

orange --- c.1300, from O.Fr. orenge (12c.), from M.L. pomum de orenge, from It. arancia, originally narancia (Venetian naranza), alt. of Arabic naranj, from Pers. narang, from Skt. naranga-s "orange tree," of uncertain origin. Loss of initial n- probably due to confusion with definite article (e.g. une narange, una narancia), but perhaps infl. by Fr. or "gold." The tree's original range probably was northern India. The Persian orange, grown widely in southern Europe after its introduction in Italy 11c., was bitter; sweet oranges were brought to Europe 15c. from India by Portuguese traders and quickly displaced the bitter variety, but only Mod.Gk. still seems to distinguish the bitter (nerantzi) from the sweet (portokali "Portuguese") orange. Portuguese, Spanish, Arab, and Dutch sailors planted citrus trees along trade routes to prevent scurvy. On his second voyage in 1493, Christopher Columbus brought the seeds of oranges, lemons and citrons to Haiti and the Caribbean. Introduced in Florida (along with lemons) in 1513 by Sp. explorer Juan Ponce de Leon. Introduced to Hawaii 1792. Not used as the name of a color until 1542.

Orangemen --- secret society founded 1795 in Belfast to promote Protestant power in N.Ireland, named for William of Orange (who became King William III of England and triumphed in Ireland at the head of a Protestant army at the Battle of the Boyne), of the Ger. House of Nassau. His cousins and their descendants constitute the royal line of Holland. The name is from the town of Orange on the Rhone in France, which became part of the Nassau principality in 1530, the town so called because it was said to have been a center for importing oranges to northern France and beyond (its Roman name was Arausio). In this roundabout way the political/religious movement of N.Ir. Protestantism acquired an association with the color orange.

orangutan --- 1699, from Du. orang-outang, from Malay orang utan, lit. "man of the woods," from orang "man" + utan, hutan "forest, wild." It is possible that the word originally was used by town-dwellers on Java to describe savage forest tribes of the Sunda Islands and that Europeans misunderstood it to mean the ape. The name is not now applied in Malay to the animal, but there is evidence that it was so in 17c.

orate --- c.1600, "to pray, to plead," from L. oratus, pp. of orare "pray, plead, speak before a court or assembly" (see orator). The meaning "make a formal speech" emerged c.1860 in Amer.Eng. as a back-formation of oration.

oration --- c.1375, "prayer," from L.L. orationem (nom. oratio) "speaking, discourse, language, prayer," from L. oratus, pp. of orare (see orator). Meaning "formal speech, discourse" first recorded 1502.

orator --- c.1374, "one who pleads or argues for a cause," from Anglo-Fr. oratour, from O.Fr. orateur (14c.), from L. oratorem (nom. orator) "speaker," from orare "speak before a court or assembly, plead," from PIE base *or- "to pronounce a ritual formula" (cf. Skt. aryanti "they praise," Homeric Gk. are, Attic ara "prayer," Hittite ariya- "to ask the oracle," aruwai- "to revere, worship"). Meaning "public speaker" is attested from c.1430.

oratorio --- long musical composition, usually with a text based on Scripture, 1727 (in Eng. 1644 in native form oratory), from It. oratorio (late 16c.), from Church L. oratorium (see oratory (2)), in ref. to musical services in the church of the Oratory of St. Philip Neri in Rome, where old mystery plays were adapted to religious services.

oratory (1) --- formal public speaking, the art of eloquence, 1586, from L. (ars) oratoria "oratorical (art)," fem. of oratorius "of speaking or pleading," from orare (see orator).

oratory (2) --- small chapel, c.1300, from L.L. oratorium "place of prayer" (especially the Oratory of St. Philip Neri in Rome, where musical services were presented), properly an adj., as in oratorium templum, from neut. of L. oratorius "of or for praying," from orare (see orator).

orb --- c.1420 (implied in orbicular), "sphere, globe," also "emblem of sovereignty," from O.Fr. orbe (13c.), from L. orbem (nom. orbis) "circle, disk, ring," probably related to orbita "wheel track, rut," of unknown origin. Some suggest a connection with the root of orchid (q.v.). A three-dimensional extension of a word originally describing two-dimensional shapes. Astronomical sense is from 1526, in ref. to the hollow spheres that carried the planets and stars in the Ptolemaic system. Orb weaver spider is first recorded 1889.

orbit (n.) --- 1392, "the eye socket," from M.L. orbita, transf. use of L. orbita "wheel track, course, orbit" (see orb). Astronomical sense first recorded 1696 in Eng.; it was in classical L., revived in Gerard of Cremona's transl. of Avicenna. The verb is attested from 1946, from the noun.

orc --- ogre, devouring monster, O.E. orcþyrs, orcneas (pl.), perhaps from a Romanic source akin to ogre, and ult. from L. Orcus "Hell," a word of unknown origin. Revived by J.R.R. Tolkien (1892-1973) as the name of a brutal race in Middle Earth.

orca --- killer whale, 1846, introduced as a generic term for the species by J. Richardson & J.E. Gray in "The zoology of the voyage of HHS 'Erebus' & 'Terror,' " from L. orca "cetacean, a kind of whale." Earlier in Eng., orc, ork "large whale" (c.1590), from Fr. orque, had been used vaguely of sea monsters (see orc).

orchard --- O.E. orceard "fruit garden," probably from wortgeard, from wort "vegetable, plant root" + geard "garden, yard" (the word also meant "vegetable garden" until 15c.), with first element infl. by L. hortus (in L.L. ortus) "garden," from PIE *ghor-to- "an enclosure," from base *gher- "to grasp, enclose" (see yard (1)).

orchestra --- 1606, "area in an ancient theater," from L. orchestra, from Gk. orkhestra, semicircular space where the chorus of dancers performed, with suffix -tra denoting place + orkheisthai "to dance," intens. of erkhesthai "to go, come," from PIE *ergh- "to set in motion, stir up, raise" (cf. Skt. rghayati "trembles, rages, raves," L. oriri "to rise"), from base *er-/*or- (cf. L. origo "a beginning;" Skt. rnoti "rises, moves," arnah "welling stream;" O.Pers. rasatiy "he comes;" Gk. ornynai "to rouse, start;" Goth. rinnan, O.E. irnan "to flow, run"). In ancient Rome, it referred to the place in the theater reserved for senators and other dignitaries. Meaning "group of musicians performing at a concert, opera, etc." first recorded 1720; "part of theater in front of the stage" is from 1768. Orchestrate "to compose or arrange (music) for an orchestra" is an 1880 back-formation of orchestration, which was borrowed 1864 from Fr. The fig. sense of orchestrate is attested from 1883.

orchid --- 1845, introduced by John Lindley in "School Botanty," from Mod.L. Orchideæ (Linnaeus), the plant's family name, from L. orchis, a kind of orchid, from Gk. orkhis (gen. orkheos) "orchid," lit. "testicle," from PIE *orghi-, the standard root for "testicle" (cf. Avestan erezi "testicles," Arm. orjik, M.Ir. uirgge, Ir. uirge "testicle," Lith. erzilas "stallion"). The plant so called because of the shape of its root. Earlier in Eng. in L. form, orchis (1562). Marred by extraneous -d- in attempt to extract the Latin stem.

ordain --- c.1290, "to appoint or admit to the ministry of the Church," from stem of O.Fr. ordener, from L. ordinare "put in order, arrange, dispose, appoint," from ordo (gen. ordinis) "order." The notion is "to confer holy orders upon" (see order). Meaning "to decree, enact" is from 1297; sense of "to set (something) that will continue in a certain order" is from c.1315.

ordeal --- O.E. ordel, lit. "judgment, verdict," from P.Gmc. noun *uzdailjam (cf. O.Fris. urdel, Du. oordeel, Ger. urteil "judgment"), lit. "that which is dealt out" (by the gods), from *uzdailijan "share out," related to O.E. adælan "to deal out" (see deal). The notion is of the kind of arduous physical test (such as walking blindfolded and barefoot between red-hot plowshares) that was believed to determine a person's guilt or innocence by immediate judgment of the deity, an ancient Teutonic mode of trial. Eng. retains a more exact sense of the word; its cognates in Ger., etc., have been generalized. Curiously absent in M.E., and perhaps reborrowed 16c. from M.L. or M.Fr., which got it from Gmc. Metaphoric extension to "anything which tests character or endurance" is attested from 1658. The prefix or- survives in Eng. only in this word, but was common in O.E. and other Gmc. languages (Goth. ur-, O.N. or-, etc.) and was originally an adv. and prep. meaning "out."

order (n.) --- c.1225, "body of persons living under a religious discipline," from O.Fr. ordre (11c.), from earlier ordene, from L. ordinem (nom. ordo) "row, rank, series, arrangement," originally "a row of threads in a loom," from Italic root *ored(h)- "to arrange, arrangement" (cf. ordiri "to begin to weave," e.g. in primordial), of unknown origin. Meaning "a rank in the (secular) community" is first recorded c.1300; meaning "command, directive" is first recorded 1548, from the notion of "to keep in order." Military and honorary orders grew our of the fraternities of Crusader knights. Business and commerce sense is attested from 1837. In natural history, as a classification of living things, it is first recorded 1760. Meaning "condition of a community which is under the rule of law" is from 1483. Phrase in order to (1655) preserves etymological notion of "sequence." The word reflects a very medieval notion: "a system of parts subject to certain uniform, established ranks or proportions," and was used of everything from architecture to angels. The verb is c.1240, from the noun. In short order "without delay" is from 1834, Amer.Eng.; order of battle is from 1769.

orderly (adv.) --- 1477, "in due order," from order (q.v.). As a noun meaning "military attendant who carries orders" it is first attested 1781 (short for orderly corporal, etc.). Extended 1809 to an attendant at a hospital (originally a military hospital) charged with keeping things in order and clean.

ordinal (n.) --- 1387, "book setting forth the order of services in the Church," from L.L. adj. ordinalis "showing order, denoting an order of succession," from L. ordo (gen. ordinis) "row, series" (see order). The adj. in Eng., "marking position in an order or series," is attested from 1599.

ordinance --- 1303, "an authoritative direction, decree, or command" (narrower or more transitory than a law), from O.Fr. ordenance, from M.L. ordinantia, from L. ordinantem (nom. ordinans), prp. of ordinare "put in order" (see ordain). By c.1330 senses had emerged of "arrangement in ranks or rows" (especially in order of battle), also "warlike provisions, equipment" (a sense now in ordnance, q.v.).

ordinary (adj.) --- c.1460, "belonging to the usual order or course," from O.Fr. ordinarie, from L. ordinarius "customary, regular, usual, orderly," from ordo (gen. ordinis) "order" (see order). Various noun usages, dating to c.1380 and common until 19c., now largely extinct except in out of the ordinary (1893). In British education, Ordinary level "lowest of the three levels of General Certificate of Education" is attested from 1947 (abbrev. O level).

ordination --- 1432, "the act of conferring holy orders," from M.Fr. ordinacion (12c.), from L. ordinationem (nom. ordinatio) "a setting in order, ordinance," from ordinatus, pp. of ordinare "arrange" (see ordain).

ordnance --- cannon, artillery, a clipped form of ordinance (q.v.) which was attested from 1390 in the sense of "military materials, provisions of war;" a sense now obsolete but which led to those of "engines for discharging missiles" (c.1430) and "branch of the military concerned with stores and materials" (1485). The shorter word was established in these distinct senses by 17c. Ordnance survey (1833), official survey of Great Britain and Ireland, was undertaken by the government under the direction of the Master-General of the Ordnance (a natural choice, because gunners have to be skilled at surveying ranges and distances).

Ordovician --- geological period following the Cambrian and preceding the Silurian, 1879, coined by Eng. geologist Charles Lapworth (1842-1920) from L. Ordovices, name of an ancient British tribe in North Wales. The period so called because rocks from it first were studied extensively in the region around Bala in North Wales. The tribe's name is Celtic, lit. "those who fight with hammers," from Celt. base *ordo "hammer" + PIE *wik- "to fight, conquer" (cf. victor).

ordure --- c.1300, from O.Fr. ordure "filth" (12c.), from ord "filthy," from L. horridus "dreadful" (see horrid).

ore --- 12c., merger of O.E. ora "ore, unworked metal" (related to ear "earth"); and O.E. ar "brass, copper, bronze," from P.Gmc. *ajiz- (cf. O.N. eir "brass, copper," Ger. ehern "brazen," Goth. aiz "bronze"), from PIE *aus- "gold" (cf. Skt. ayah "metal," Avestan ayo, L. aes "brass"). The two words were not fully assimilated till 17c.; what emerged has the form of ar but the meaning of ora.

ore rotundo --- 1720, from L., lit. "with round mouth," from abl. of os "mouth" + abl. of rotundus "round." From Horace ("Grais ingenium, Grais dedit ore rotundo Musa loqui," in "Ars Poetica").

oread --- c.1586, from L. Oreas (gen. Oreadis), from Gk. oreias "mountain nymph," from oros "mountain," probably from PIE base *er-/*or- "to raise" (cf. Skt. rsvah "high," L. oriri "to raise;" see orchestra).

oregano --- 1771, from Sp./Sp. Amer. oregano, from L. origanus, origanum, from Gk. oreiganon, from oros "mountain" (see oread) + ganos "brightness, ornament." The older form of the word in Eng. was the L.-derived origanum (c.1265), also origan (c.1420). In Europe, the dried leaves of wild marjoram; in America, a different, and more pungent, shrub.

Oregon --- 1765 as the name of a large river in the west of North America, probably the modern Columbia; of uncertain and disputed origin. It seems to be of Algonquian origin.

Oreo --- derogatory word for "black person felt to have a 'white' mentality," 1968, black Amer.Eng., from the snack cookies, which consist of dark chocolate wafers and white sugar cream filling (hence "brown outside, white inside"). The cookies (made by Nabisco) date from 1912; the source of the name has been forgotten.

Orestes --- son of Agamemnon and Clytemnestra, from Gk., lit. "mountaineer," from oros "mountain" (see oread).

organ --- O.E. organe, and O.Fr. orgene (12c.), both meaning "musical instrument," both from L. organa, pl. of organum, from Gk. organon "implement, musical instrument, organ of the body," lit. "that with which one works," from PIE *werg-ano-, from base *werg- "to do," related to Gk. ergon "work" and O.E. weorc (see urge (v.)). Applied vaguely in late O.E. to musical instruments; sense narrowed by c.1386 to the modern musical instrument known by that name (involving pipes supplied with wind by a bellows and worked by means of keys), though Augustine (c.400) knew this as a specific sense of L. organa. The meaning "body part adapted to a certain function" is attested from 1392. Organist is first recorded 1591; organ-grinder is attested from 1806.

organic --- 1517, "serving as an organ or instrument," from L. organicus, from Gk. organikos "of or pertaining to an organ," from organon "instrument" (see organ). Sense of "from organized living beings" is first recorded 1778 (earlier this sense was in organical, c.1450). Meaning "free from pesticides and fertilizers" first attested 1942.

organism --- 1664, "organic structure, organization," from organize (q.v.). Sense of "living animal or plant" first recorded 1842.

organize --- 1413, from M.L. organizare, from L. organum "instrument, organ." Organization (1432) is originally in the sense "act of organizing," from M.L. organizationem (nom. organizatio), from organizare; meaning "condition of being organized" is first attested 1790; that of "action of organizing parts into a whole" is 1816; that of "system, establishment" is 1873. Organization man "one who subverts his individuality to the organization that employs him" (1956) is from the title of W.H. Whyte's book.

orgasm (n.) --- 1684, from Fr. orgasme, from Gk. orgasmos "excitement, swelling," from organ "be in heat, become ripe for," lit. "to swell, be excited," related to orge "impulse, excitement, anger," from PIE base *wrog- "to burgeon, swell with strength" (cf. Skt. urja "a nourishment, sap, vigor," O.Ir. ferc, ferg "anger"). The verb is attested from 1973, originally and usually in ref. to a woman's sexual climax. Orgasmic is attested from 1935.