overthrow (n.) Look up overthrow at Dictionary.com
1510s, "act of overthrowing," from over- + throw (n.).
overtime (n.) Look up overtime at Dictionary.com
"time above the regular hours of work," 1846, from over- + time (n.). Sporting sense first attested 1921, in an ice hockey context.
overtire (v.) Look up overtire at Dictionary.com
1550s, from over- + tire (v.). Related: Overtired; overtiring.
overtly (adv.) Look up overtly at Dictionary.com
early 14c., from overt + -ly (2).
overtone (n.) Look up overtone at Dictionary.com
1867, in literal sense, from over + tone (n.); a loan-translation of German Oberton, first used by German physicist Hermann Ludwig Ferdinand von Helmholtz (1821-1894) as a contraction of Overpartialton "upper partial tone." Figurative sense of "subtle implication" is from 1890, first attested in writings of William James.
overtop (v.) Look up overtop at Dictionary.com
1560s, from over- + top (v.). Related: Overtopped; overtopping.
overtower (v.) Look up overtower at Dictionary.com
1830, from over- + tower (v.). Related: Overtowered; overtowering.
overture (n.) Look up overture at Dictionary.com
mid-13c., "opening, aperture;" early 15c. as "an introductory proposal," from Old French overture "opening; proposal" (Modern French ouverture), from Latin apertura "opening," from aperire "to open, uncover" (see overt). Orchestral sense first recorded in English 1660s.
overturn (v.) Look up overturn at Dictionary.com
early 13c., of a wheel, "to rotate, roll over," from over- + turn (v.). Attested from c. 1300 in general transitive sense "to throw over violently;" figurative meaning "to ruin, destroy" is from late 14c. Of judicial decisions, "to reverse," it is attested from 1826. Related: Overturned; overturning.
overuse (n.) Look up overuse at Dictionary.com
also over-use, 1862, from over- + use (n.).
overview (n.) Look up overview at Dictionary.com
"survey, summary," 1934, American English, from over- + view (n.). In 17c. it meant "inspection, supervision," but this became obsolete.
overweening (adj.) Look up overweening at Dictionary.com
mid-14c., from present participle of verb overwenen "be conceited, presume, be presumptuous, be over-confident," from Old English oferwenian "to be proud, become insolent or presumptuous;" see over- + ween.
overweight (adj.) Look up overweight at Dictionary.com
"in excess of proper or ordinary weight," 1630s, from over- + weight (n.). Of persons, as a noun, "obesity" from 1917.
overwhelm (v.) Look up overwhelm at Dictionary.com
early 14c., "to turn upside down, to overthrow," from over- + Middle English whelmen "to turn upside down" (see whelm). Meaning "to submerge completely" is mid-15c. Perhaps the connecting notion is a boat, etc., washed over, and overset, by a big wave. Figurative sense of "to bring to ruin" is attested from 1520s. Related: Overwhelmed; overwhelming; overwhelmingly.
overwhelmed (adj.) Look up overwhelmed at Dictionary.com
mid-15c., past participle adjective from overwhelm.
overwinter (v.) Look up overwinter at Dictionary.com
Old English oferwintran; see over- + winter (v.). Related: Overwintered; overwintering.
overwork (v.) Look up overwork at Dictionary.com
"to cause to work too hard," 1520s, from over- + work (v.). Old English oferwyrcan meant "to work all over," i.e. "to decorate the whole surface of." Related: Overworked; overworking.
overwork (n.) Look up overwork at Dictionary.com
"work beyond a person's strength," 1819; see overwork (v.). Old English oferweorc meant "a superstructure, sarcophagus, tomb."
overwrite (v.) Look up overwrite at Dictionary.com
1690s, "to write over other writing," from over- + write (v.). Of computers, it is attested from 1959. Meaning "to write too elaborately or ornately" is from 1923. Related: Overwriting; overwritten.
overwrought (adj.) Look up overwrought at Dictionary.com
"worked up to too high a pitch," 1825, literally "over-worked," from over- + wrought. Earlier it meant "exhausted by work" (1660s) as a literal past participle of overwork.
overzealous (adj.) Look up overzealous at Dictionary.com
also over-zealous, 1630s, from over- + zealous. Related: Overzealously; overzealousness.
Ovid Look up Ovid at Dictionary.com
Publius Ovidius Nasso, Roman poet (43 B.C.E.-17 C.E.). Related: Ovidian.
oviduct (n.) Look up oviduct at Dictionary.com
1757, from Modern Latin oviductus, from ovi ductus "channel of an egg;" see egg (n.) + duke (n.).
oviform (adj.) Look up oviform at Dictionary.com
"egg-shaped," 1680s, from ovi-, comb. form of Latin ovus "egg" (see ovum) + forma "form, shape" (see form (n.)).
ovine (adj.) Look up ovine at Dictionary.com
"pertaining to or of the nature of sheep," 1828, from Latin ovinus, from ovis "sheep," from PIE Related: *owi- "sheep" (see ewe).
oviparous (adj.) Look up oviparous at Dictionary.com
"producing eggs that are hatched outside the body of the female," 1640s, from Latin oviparus, from ovum "egg" (see egg (n.)) + stem of parere "to bring forth" (see pare).
ovoid (adj.) Look up ovoid at Dictionary.com
"egg-shaped," 1828, from Modern Latin ovoides, a hybrid from Latin ovum (see ovum) + Greek -oeides "like" (see -oid). Related: Ovoidal.
ovoviviparous (adj.) Look up ovoviviparous at Dictionary.com
1801, from comb. form of ovum + viviparous.
ovular (adj.) Look up ovular at Dictionary.com
1855, from ovule + -ar.
ovulate (v.) Look up ovulate at Dictionary.com
1888, back-formation from ovulation. Related: Ovulated; ovulating.
ovulation (n.) Look up ovulation at Dictionary.com
1848, from Modern Latin ovulum (see ovule) + noun ending -ation.
ovule (n.) Look up ovule at Dictionary.com
1821, from French ovule and directly from Modern Latin ovulum, literally "small egg," diminutive of Latin ovum "egg" (see ovum).
ovum (n.) Look up ovum at Dictionary.com
(plural ova), 1706, from Latin ovum "egg," cognate with Greek oon, Old Norse egg, Old English æg, all perhaps from PIE root *awi- (see egg (n.)).
ow (interj.) Look up ow at Dictionary.com
14c. as an exclamation of surprise; 1919 as an expression of sudden pain.
owe (v.) Look up owe at Dictionary.com
Old English agan (past tense ahte) "to have, own," from Proto-Germanic *aigan "to possess" (source also of Old Frisian aga, Old Norse eiga, Old High German eigan, Gothic aigan "to possess, have"), from PIE *aik- "to be master of, possess" (source also of Sanskrit ise "he owns," isah "owner, lord, ruler;" Avestan is- "riches," isvan- "well-off, rich").

Sense of "to have to repay" began in late Old English with the phrase agan to geldanne literally "to own to yield," which was used to translate Latin debere (earlier in Old English this would have been sceal "shall"); by late 12c. the phrase had been shortened to simply agan, and own (v.) took over this word's original sense.

An original Germanic preterite-present verb (along with can (v.1), dare, may, etc.). New past tense form owed arose 15c. to replace oughte, which developed into ought (v.).
Owen Look up Owen at Dictionary.com
Celtic masc. proper name, ultimately from Greek eugenes "well-born;" via Gaelic Eòghann, Old Irish Eogán, Old Welsh Eugein, Ougein. In Medieval records, frequently Latinized as Eugenius; the form Eugene emerged in Scotland by late 12c. The Breton form Even led to modern French Ivain. Owenite in reference to the communistic system of social reformer Robert Owen (1771-1858) is attested from 1829.
owl (n.) Look up owl at Dictionary.com
Old English ule "owl," from Proto-Germanic *uwwalon- (source also of Middle Dutch, Dutch uil, Old High German uwila, German Eule, Old Norse ugla), a diminutive of PIE root *u(wa)l-, which is imitative of a wail or an owl's hoot (compare Latin ulula "owl;" also see ululation). The bird was employed proverbially and figuratively in reference to nocturnal habits, ugliness, and appearance of gravity and wisdom (often ironic).
owlish (adj.) Look up owlish at Dictionary.com
1610s, from owl + -ish. Related: Owlishly; owlishness.
own (adj.) Look up own at Dictionary.com
Old English agen "one's own," literally "possessed by," from Proto-Germanic *aigana- "possessed, owned" (source also of Old Saxon egan, Old Frisian egin, Old Norse eiginn, Dutch eigen, German eigen "own"), from past participle of PIE *aik- "to be master of, possess," source of Old English agan "to have" (see owe).
own (v.) Look up own at Dictionary.com
c. 1200, ouen, "to possess, have; rule, be in command of, have authority over;" from Old English geagnian, from root agan "to have, to own" (see owe), and in part from the adjective own (q.v.). It became obsolete after c. 1300, but was revived early 17c., in part as a back-formation of owner (mid-14c.), which continued. From c. 1300 as "to acknowledge, admit as a fact," said especially of things to one's disadvantage. To own up "make full confession" is from 1853. Related: Owned; owning.
owned (adj.) Look up owned at Dictionary.com
"possessed," 1620s, past participle adjective from own (v.).
owner (n.) Look up owner at Dictionary.com
mid-14c., agent noun from own (v.).
ownership (n.) Look up ownership at Dictionary.com
1580s, from owner + -ship. Ownership society (2003) was popularized by U.S. president George W. Bush.
ox (n.) Look up ox at Dictionary.com
Old English oxa "ox" (plural oxan), from Proto-Germanic *ukhson (source also of Old Norse oxi, Old Frisian oxa, Middle Dutch osse, Old Saxon, Old High German ohso, German Ochse, Gothic auhsa), from PIE *uks-en- "male animal," (source also of Welsh ych "ox," Middle Irish oss "stag," Sanskrit uksa, Avestan uxshan- "ox, bull"), said to be from root *uks- "to sprinkle," related to *ugw- "wet, moist." The animal word, then, is literally "besprinkler."
ox-eyed (adj.) Look up ox-eyed at Dictionary.com
1620s, from ox + eye (n.).
ox-hide Look up ox-hide at Dictionary.com
late 15c., from ox + hide (n.1).
oxalic (adj.) Look up oxalic at Dictionary.com
1791, from French oxalique (1787, Lavoisier), from Latin oxalis "sorrel," from Greek oxalis, from oxys "sharp" (see acro-). So called because it occurs in sorrel.
oxbow (n.) Look up oxbow at Dictionary.com
also ox-bow, mid-14c., "wooden collar for an ox," from ox + bow (n.1). Meaning "semicircular bend in a river" is from 1797, American English (New England); meaning "curved lake left after an oxbow meander has been cut off by a change in the river course" is from 1898. The reference is to similarity of shape.
Oxbridge Look up Oxbridge at Dictionary.com
1849, a conflation of Oxford and Cambridge, used in reference to the characteristics common to the two universities.
oxen (n.) Look up oxen at Dictionary.com
plural of ox, it is the only true continuous survival in Modern English of the Old English weak plural. OED reports oxes occurs 14c.-16c., "but has not survived."