ream (n.1) Look up ream at Dictionary.com
measure of paper, mid-14c., from Old French reyme, from Spanish resma, from Arabic rizmah "bundle" (of paper), from rasama "collect into a bundle." The Moors brought manufacture of cotton paper to Spain.

Early variant rym (late 15c.) suggests a Dutch influence (compare Dutch riem), probably borrowed from Spanish during the time of Hapsburg control of Holland. For ordinary writing paper, 20 quires of 24 sheets each, or 480 sheets; often 500 or more to allow for waste; slightly different numbers for drawing or printing paper.
ream (v.) Look up ream at Dictionary.com
"to enlarge a hole," 1815, probably a southwest England dialectal survival from Middle English reme "to make room, open up," from Old English ryman "widen, extend, enlarge," from Proto-Germanic *rumijan (cognates: Old Saxon rumian, Old Norse ryma, Old Frisian rema, Old High German rumen "to make room, widen"), from *rumaz "spacious" (see room (n.)). Slang meaning "to cheat, swindle" first recorded 1914; anal sex sense is from 1942. To ream (someone) out "scold, reprimand" is recorded from 1950.
ream (n.2) Look up ream at Dictionary.com
"cream" (obsolete), Old English ream, from Proto-Germanic *raumoz (cognates: Middle Dutch and Dutch room, German Rahm), of uncertain origin.
reap (v.) Look up reap at Dictionary.com
"to cut grain with a hook or sickle," Old English reopan, Mercian form of ripan "to reap," related to Old English ripe "ripe" (see ripe). Related: Reaped; reaping.
reaper (n.) Look up reaper at Dictionary.com
Old English ripere, agent noun from reap (v.). As the name of a personification of death, from 1839.
rear (n.) Look up rear at Dictionary.com
"hindmost part," c.1600, abstracted from rerewarde "rear guard, hindmost part of an army or fleet" (mid-14c.), from Anglo-French rerewarde, Old French rieregarde, from Old French adverb riere "behind" (from Latin retro "back, behind;" see retro-) + Old French garde (see guard (n.)). Or the word may be a shortened form of arrear (see arrears).

As a euphemism for "buttocks" it is attested from 1796. Rear admiral is first attested 1580s, apparently so called from ranking "behind" an admiral proper. Rear-view (mirror) is recorded from 1926.
rear (v.1) Look up rear at Dictionary.com
Old English ræran "to raise, build up, create, set on end; arouse, excite, stir up," from Proto-Germanic *raizijanau "to raise," causative of *risanan "to rise" (see raise (v.)). Meaning "bring into being, bring up" (as a child) is recorded from early 15c.; that of "raise up on the hind legs" is first recorded late 14c. Related: Reared; rearing.
rear (adj.) Look up rear at Dictionary.com
c.1300, from Old French rere (see rear (n.)).
rear (v.2) Look up rear at Dictionary.com
"attack in the rear," 17c., from rear (n.).
rear-end (n.) Look up rear-end at Dictionary.com
"buttocks," 1937, from rear (adj.) + end (n.). As a verb, "to collide (with another vehicle) from behind," from 1976. Related: Rear-ended; rear-ending.
rearward (adv.) Look up rearward at Dictionary.com
1590s, from rear (adj.) + -ward.
reason (n.) Look up reason at Dictionary.com
c.1200, "intellectual faculty that adopts actions to ends," also "statement in an argument, statement of explanation or justification," from Anglo-French resoun, Old French raison "course; matter; subject; language, speech; thought, opinion," from Latin rationem (nominative ratio) "reckoning, understanding, motive, cause," from ratus, past participle of reri "to reckon, think," from PIE root *re(i)- "to reason, count" (source of Old English rædan "to advise;" see read (v.)).

Meaning "sanity; degree of intelligence that distinguishes men from brutes" is recorded from late 13c. Sense of "grounds for action, motive, cause of an event" is from c.1300. Middle English sense of "meaning, signification" (early 14c.) is in the phrase rhyme or reason. Phrase it stands to reason is from 1630s. Age of Reason "the Enlightenment" is first recorded 1794, as the title of Tom Paine's book.
reason (v.) Look up reason at Dictionary.com
early 14c., resunmen, "to question (someone)," also "to challenge," from Old French raisoner "speak, discuss; argue; address; speak to," from Late Latin rationare "to discourse," from ratio (see reason (n.)). Intransitive sense of "to think in a logical manner" is from 1590s; transitive sense of "employ reasoning (with someone)" is from 1847. Related: Reasoned; reasoning.
reasonable (adj.) Look up reasonable at Dictionary.com
c.1300, "having sound judgment, sane, rational," from Old French raisonable, from Latin rationabilis, from ratio (see reason (n.)).
What the majority of people consider to be 'reasonable' is that about which there is agreement, if not among all, at least among a substantial number of people; 'reasonable' for most people, has nothing to do with reason, but with consensus. [Erich Fromm, "The Heart of Man," 1968]
Meaning "moderate in price" is recorded from 1660s. Related: Reasonably.
reasoning (n.) Look up reasoning at Dictionary.com
late 14c., "exercise of the power of reason; act or process of thinking logically;" also "an instance of this;" verbal noun from reason (v.).
reassurance (n.) Look up reassurance at Dictionary.com
also re-assurance, 1610s, from reassure + -ance.
reassure (v.) Look up reassure at Dictionary.com
"restore (someone) to confidence," 1590s, from re- "back, again" + assure. Related: Reassured; reassuring.
reattach (v.) Look up reattach at Dictionary.com
also re-attach, c.1600 in law; 1813 in a literal sense, from re- + attach. Related: Reattached; reattaching.
reave (v.) Look up reave at Dictionary.com
Old English reafian "to rob (something from someone), plunder, pillage," from Proto-Germanic *raubjon (cognates: Old Frisian ravia, Middle Dutch roven, Dutch rooven, Old High German roubon, German rauben), from PIE *reup- "to snatch" (see rip (v.)). Related: Reaved; reaving.
reaver (n.) Look up reaver at Dictionary.com
Old English reafere "plundering forager," agent noun from reafian (see reave (v.)). Similar formation in Old Frisian ravere, Middle Dutch rover, Dutch roover, Old High German roubari, German Räuber.
reb (n.) Look up reb at Dictionary.com
abbreviation of rebel (n.), 1862, in U.S. Civil War context.
rebar (n.) Look up rebar at Dictionary.com
also re-bar, "steel reinforcing rod in concrete," 1961, from re(inforced) bar.
rebarbative (adj.) Look up rebarbative at Dictionary.com
"repellent, unattractive," 1885, from French rébarbatif (14c.), from barbe "beard," from Latin barba (see barb (n.)).
rebate (v.) Look up rebate at Dictionary.com
late 14c., "to reduce;" early 15c., "to deduct, subtract," from Old French rabattre "beat down, drive back," also "deduct," from re- "repeatedly" (see re-) + abattre "beat down" (see abate). Meaning "to pay back (a sum) as a rebate" is from 1957. Related: Rebated; rebating.
rebate (n.) Look up rebate at Dictionary.com
1650s, from rebate (v.).
rebbe (n.) Look up rebbe at Dictionary.com
1881, from Yiddish, from Hebrew rabbi (see rabbi).
rebec (n.) Look up rebec at Dictionary.com
medieval stringed musical instrument, early 15c., from Middle French rebec (15c.), an unexplained alteration (perhaps somehow influenced by bec "beak") of Old French ribabe (13c.), ultimately from Arabic rebab. Compare Old Provençal rebec, Italian ribeca. It has three strings and is played with a bow.
Rebecca Look up Rebecca at Dictionary.com
fem. proper name, biblical wife of Isaac, mother of Jacob and Esau, from Late Latin Rebecca, from Greek Rhebekka, from Hebrew Ribhqeh, literally "connection" (compare ribhqah "team"), from Semitic base r-b-q "to tie, couple, join" (compare Arabic rabaqa "he tied fast"). Rebekah, the form of the name in Authorized Version, was taken as the name of a society of women (founded 1851 in Indiana, U.S.) as a complement to the Odd Fellows.
rebel (adj.) Look up rebel at Dictionary.com
c.1300, from Old French rebelle "stubborn, obstinate, rebellious" (12c.) and directly from Latin rebellis "insurgent, rebellious," from rebellare "to rebel, revolt," from re- "opposite, against," or perhaps "again" (see re-) + bellare "wage war," from bellum "war."
rebel (v.) Look up rebel at Dictionary.com
mid-14c., from Old French rebeller (14c.), from Latin rebellare "to revolt" (see rebel (adj.)). Related: Rebelled; rebelling.
rebel (n.) Look up rebel at Dictionary.com
"person who makes war on his country for political motives," mid-14c., from rebel (adj.). Meaning "supporter of the American cause in the War of Independence" is from 1775; sense of "supporter of the Southern cause in the American Civil War" is attested from April 15, 1861. Rebel yell in an American Civil War context attested from 1862, but the thing itself is older and was said to have been picked up by southwestern men in their periodic wars against the Indians.
The Southern troops, when charging or to express their delight, always yell in a manner peculiar to themselves. The Yankee cheer is more like ours; but the Confederate officers declare that the rebel yell has a particular merit, and always produces a salutary and useful effect upon their adversaries. A corps is sometimes spoken of as a 'good yelling regiment.' [A.J.L. Fremantle, "The Battle of Gettysburg and the Campaign in Pennsylvania," in "Blackwood's Edinburgh Magazine," Sept. 1863]
rebellion (n.) Look up rebellion at Dictionary.com
"war waged against a government by some portion of its subjects," mid-14c., from Old French rebellion (14c.) and directly from Latin rebellionem (nominative rebellio) "rebellion, revolt; renewal of war," from rebellis (see rebel (adj.)).
rebellious (adj.) Look up rebellious at Dictionary.com
early 15c., from Latin rebellis (see rebel (adj.)) + -ous. Related: Rebelliously; rebelliousness.
rebirth (n.) Look up rebirth at Dictionary.com
1812, "reincarnation;" 1833, "renewed life or activity," from re- + birth (n.).
reboot (v.) Look up reboot at Dictionary.com
1981, from re- + boot (v.) in the computer sense. Related: Rebooted; rebooting.
rebop (n.) Look up rebop at Dictionary.com
see bebop.
reborn (adj.) Look up reborn at Dictionary.com
1590s, from re- "back, again" + born.
reborrow (v.) Look up reborrow at Dictionary.com
1630s, from re- "back, again" + borrow. Related: Reborrowed; reborrowing.
rebound (v.) Look up rebound at Dictionary.com
late 14c., "to spring, leap," also "return to afflict" (early 15c.), from Old French rebondir "leap back, resound; repulse, push back," from re- "back" (see re-) + bondir "leap, bound" (see bound (v.)). Sense of "to spring back from force of impact" is recorded from late 14c. Sports use probably first in tennis; basketball sense is attested from 1914. Related: Rebounded; rebounding.
rebound (n.) Look up rebound at Dictionary.com
1520s, in reference to a ball, from rebound (v.). Sense in basketball from 1920 (from 1917 in ice hockey). Meaning "period of reaction or renewed activity after disturbance" is from 1570s.
rebroadcast (v.) Look up rebroadcast at Dictionary.com
also re-broadcast, 1923, from re- + broadcast (v.). Related: Rebroadcasting.
rebuff (v.) Look up rebuff at Dictionary.com
1580s, from obsolete French rebuffer "to check, snub," from Italian ribuffare "to check, chide, snide," from ribuffo "a snub," from ri- "back" (from Latin re-, see re-) + buffo "a puff," of imitative origin (compare buffet (v.)). Related: Rebuffed; rebuffing.
rebuff (n.) Look up rebuff at Dictionary.com
1610s, from rebuff (v.), or from Middle French rebuffe or Italian ribuffo.
rebuild (v.) Look up rebuild at Dictionary.com
c.1600 (implied in rebuilding), from re- "back, again" + build (v.). Related: Rebuilt.
rebuke (v.) Look up rebuke at Dictionary.com
early 14c., "to reprimand, reprove; chide, scold," from Anglo-French rebuker "to repel, beat back," Old French rebuchier, from re- "back" (see re-) + buschier "to strike, chop wood," from busche (French bûche) "wood," from Proto-Germanic *busk- (see bush (n.)). Related: Rebuked; rebuking.
rebuke (n.) Look up rebuke at Dictionary.com
early 15c., "a reproof, reprimand," from rebuke (v.).
rebus (n.) Look up rebus at Dictionary.com
c.1600, from Latin rebus "by means of objects," ablative plural of res "thing, object." According to French sources, principally from the phrase de rebus quæ geruntur "of things which are going on," in reference to the satirical pieces composed by Picardy clerks at carnivals, subtle satires of current events using pictures to suggest words, phrases or things. Or it may be from the representations being non verbis sed rebus "not by words, but by things." In either case from Latin res "thing."
rebut (v.) Look up rebut at Dictionary.com
c.1300, "to thrust back," from Old French reboter, rebuter "to thrust back," from re- "back" (see re-) + boter "to thrust, hit" (see butt (v.)). Legalese sense of "try to disprove, refute by evidence or argument" is from 1817. Related: Rebutted; rebutting.
rebuttal (n.) Look up rebuttal at Dictionary.com
1793, from rebut + -al (2). Earlier were rebutment (1590s) and rebutter (1530s, in law).
rec (n.) Look up rec at Dictionary.com
1929 as a shortening of recreation.