Oxfam Look up Oxfam at Dictionary.com
1963, short for Oxford Committee for Famine Relief.
Oxford Look up Oxford at Dictionary.com
university town in England, Middle English Oxforde, from Old English Oxnaforda (10c.) literally "where the oxen ford." In reference to a type of shoe laced over the instep, it is attested from 1721 (Oxford-cut shoes). Related: Oxfordian; Oxfordish; Oxfordist; Oxfordy.
oxidant (n.) Look up oxidant at Dictionary.com
1859, from French oxidant (1806), from oxider (see oxidation).
oxidation (n.) Look up oxidation at Dictionary.com
1791, from French oxidation (1787), coined by G. de Morveau and A. Lavoisier, noun of action from oxider "oxidize," from oxide (see oxide).
oxide (n.) Look up oxide at Dictionary.com
"compound of oxygen with another element," 1790, from French oxide (1787), coined by G. de Morveau and A. Lavoisier from ox(ygène) (see oxygen) + (ac)ide "acid" (see acid).
oxidize (v.) Look up oxidize at Dictionary.com
1802 (implied in oxidizable), from oxide + -ize. Related: Oxidized; oxidizing; oxidization.
oxidizer (n.) Look up oxidizer at Dictionary.com
1875, agent noun from oxidize.
Oxo Look up Oxo at Dictionary.com
proper name of a brand of beef extract, 1899, British.
Oxonian (adj.) Look up Oxonian at Dictionary.com
"pertaining to Oxford or to Oxford University," 1640s, from Medieval Latin oxonia, Latinized form of Middle English Oxforde (see Oxford). Earlier as a noun (1540s).
oxtail (n.) Look up oxtail at Dictionary.com
Old English oxan tægl; see ox + tail (n.1).
oxy- Look up oxy- at Dictionary.com
word-forming element meaning "sharp, pointed; acid," from Greek oxy-, comb. form of oxys "sharp, pungent" (see acro-). Also used as a comb. form of oxygen.
oxycodone (n.) Look up oxycodone at Dictionary.com
from (hydr)oxy(l) + codeine. Developed 1916 in Germany; introduced in U.S. 1939.
OxyContin Look up OxyContin at Dictionary.com
brand name of an oxycodone compound marketed in U.S. from 1996. Second element from continuous (i.e. "time-released").
oxygen (n.) Look up oxygen at Dictionary.com
gaseous chemical element, 1790, from French oxygène, coined in 1777 by French chemist Antoine-Laurent Lavoisier (1743-1794), from Greek oxys "sharp, acid" (see acro-) + French -gène "something that produces" (from Greek -genes "formation, creation;" see -gen).

Intended to mean "acidifying (principle)," it was a Greeking of French principe acidifiant. So called because oxygen was then considered essential in the formation of acids (it is now known not to be). The element was isolated by Priestley (1774), who, using the old model of chemistry, called it dephlogisticated air. The downfall of the phlogiston theory required a new name, which Lavoisier provided.
oxymoron (n.) Look up oxymoron at Dictionary.com
1650s, from Greek oxymoron, noun use of neuter of oxymoros (adj.) "pointedly foolish," from oxys "sharp, pointed" (see acro-) + moros "stupid" (see moron). Rhetorical figure by which contradictory terms are conjoined so as to give point to the statement or expression; the word itself is an illustration of the thing. Now often used loosely to mean "contradiction in terms." Related: Oxymoronic.
oy Look up oy at Dictionary.com
Yiddish exclamation of dismay, 1892, American English. Extended form oy vey (1959) includes Yiddish vey, from German Weh "woe" (see woe).
oyer (n.) Look up oyer at Dictionary.com
early 15c., "a hearing of causes," from Anglo-French oyer, Old French oir, from Latin audire "to hear" (see audience). Especially in phrase oyer and terminer (early 15c., but from late 13c. in Anglo-Latin and Anglo-French), literally "a hearing and determining," in England a court of judges of assize, in U.S. a higher criminal court.
oyez (interj.) Look up oyez at Dictionary.com
early 15c., from Anglo-French oyez "hear ye!" (late 13c., Old French oiez), a cry uttered (usually thrice) to call attention, from Latin subjunctive audiatis, plural imperative of audire "to hear" (Anglo-French oier; see audience).
oyster (n.) Look up oyster at Dictionary.com
early 14c., from Old French oistre (Modern French huître), from Latin ostrea, plural or fem. of ostreum "oyster," from Greek ostreon, from PIE *ost- "bone" (see osseous). Related to Greek ostrakon "hard shell" and to osteon "bone." The h- in the modern French word is a regular development; compare huile "oil" (Latin oleum), huit "eight" (Latin octo).
Why then the world's mine Oyster, which I, with sword will open. [Shakespeare, "The Merry Wives of Windsor," II.ii.2]
Oz Look up Oz at Dictionary.com
mythical land in L. Frank Baum's "The Wonderful Wizard of Oz" (1900) and sequels; according to an anecdote written by Baum in 1903, inspired by a three-drawer desktop cabinet letter file, the last drawer labeled O-Z. As Australian slang for "Australia," attested by 1983.
oz. Look up oz. at Dictionary.com
abbreviation of ounce (n.1), 1540s, from Italian oz. (15c.), abbreviation of onza.
Ozark Look up Ozark at Dictionary.com
mountains of southcentral United States, said to be from French aux Arcs, short for aux Arkansas "to the Arkansas (Indians)," who once inhabited that region. See Arkansas.
Ozarks Look up Ozarks at Dictionary.com
see Ozark.
ozone (n.) Look up ozone at Dictionary.com
1840, from German Ozon, coined in 1840 by German chemist Christian Friedrich Schönbein (1799-1868) from Greek ozon, neuter present participle of ozein "to smell" (see odor). So called for its pungent odor.