reverie (n.)
mid-14c., reuerye, "wild conduct, frolic," from Old French reverie, resverie "revelry, raving, delirium" (Modern French rêverie), from resver "to dream, wander, rave" (12c., Modern French rêver), of uncertain origin (also the root of rave). Meaning "daydream" is first attested 1650s, a reborrowing from French. As a type of musical composition, it is attested from 1880. Related: Reverist.
reversal (n.)
late 15c., from reverse (v.) + -al (2).
reverse (adj.)
c.1300, from Old French revers "reverse, cross, opposite" (13c.), from Latin reversus, past participle of revertere "turn back, turn about, come back, return" (see revert). Reverse angle in film-making is from 1934. Reverse discrimination is attested from 1962, American English.
reverse (n.)
mid-14c., "opposite or contrary" (of something), from reverse (adj.) or from Old French Related: revers "the opposite, reverse." Meaning "a defeat, a change of fortune" is from 1520s; meaning "back side of a coin" is from 1620s. Of gear-shifts in motor cars, from 1875. As a type of sports play (originally rugby) it is recorded from 1921.
reverse (v.)
early 14c. (transitive), "change, alter;" early 15c. (intransitive), "go backward," from Old French reverser "reverse, turn around; roll, turn up" (12c.), from Late Latin reversare "turn about, turn back," frequentative of Latin revertere (see revert). Related: Reversed; reversing.
reversible (adj.)
1640s, from reverse (v.) + -ible. As a noun, of garments, from 1863. Related: Reversable (1580s).
reversion (n.)
late 14c., from Old French reversion, from Latin reversionem (nominative reversio) "act of turning back," noun of action from past participle stem of revertere (see revert).
revert (v.)
c.1300, "to come to oneself again," from Old French revertir "return, change back," from Vulgar Latin *revertire, variant of Latin revertere "turn back, turn about; come back, return," from re- "back" (see re-) + vertere "to turn" (see versus). Of position or property from mid-15c.; application to customs and ideas is from 1610s.
revetment (n.)
1779, from French revêtement, Old French revestiment, from revestir (Modern French revêtir), from Late Latin revestire "to clothe again," from re- (see re-) + Latin vestire "to clothe" (see vest (v.)).
review (n.)
mid-15c., "an inspection of military forces," from Middle French reveue "a reviewing, review," noun use of fem. past participle of reveeir "to see again, go to see again," from Latin revidere, from re- "again" (see re-) + videre "to see" (see vision). Sense of "process of going over again" is from 1560s; that of "a view of the past, a retrospective survey" is from c.1600. Meaning "general examination or criticism of a recent work" is first attested 1640s.
review (v.)
1570s, "examine again," from re- + view (v.). Meaning "look back on" is from 1751; that of "consider or discuss critically" is from 1781. Related: Reviewed; reviewing.
reviewer (n.)
1610s, "one who reviews" (in any sense), agent noun from review (v.). Specifically, "one who critically examines and passes judgment on new publications or productions; a writer of reviews" is from 1650s.
revile (v.)
c.1300, from Old French reviler "consider vile, despise, scorn," from re-, intensive prefix (see re-), + aviler "make vile or cheap, disesteem," from vil (see vile). Related: Reviled; reviling.
revilement (n.)
1580s, from revile + -ment.
revise (v.)
1560s, "to look at again," from Middle French reviser (13c.), from Latin revisere "look at again, visit again, look back on," frequentative of revidere (past participle revisus), from re- "again" (see re-) + videre "to see" (see vision). Meaning "to look over again with intent to improve or amend" is recorded from 1590s. Related: Revised; revising.
revised (adj.)
past participle adjective from revise. Revised Version of the Bible was done 1870-84; so called because it was a revision of the 1611 ("King James") translation, also known as the Authorized Version.
revision (n.)
1610s, "act of revising," from French révision, from Late Latin revisionem (nominative revisio) "a seeing again," noun of action from past participle stem of Latin revidere (see revise). Meaning "a product of revision" is from 1845.
revisionism (n.)
1903, from revision + -ism. Originally in Marxist jargon, "rejection of gradual introduction of socialism." Revisionist is from 1850 (adj.); 1854 (n.); in the historical sense from 1934, originally with reference to the causes of World War I.
revisit (v.)
1520s, from Middle French revisiter, from re- (see re-) + visiter "to visit" (see visit (v.)). Related: Revisited; revisiting.
revitalization (n.)
1869, noun of action from revitalize.
revitalize (v.)
1840, from re- "back, again" + vitalize. Related: Revitalized; revitalizing.
revival (n.)
1650s, "act of reviving;" 1660s, "the bringing of an old play back to the stage," from revive + -al (2). First in sense "general religious awakening in a community" by Cotton Mather, 1702; revivalist is first attested 1812.
revive (v.)
early 15c., "return to consciousness; restore to health," from Middle French revivre (10c.), from Latin revivere "to live again," from re- "again" (see re-) + vivere "to live" (see vital). Meaning "bring back to notice or fashion" is from mid-15c. Related: Revived; reviving.
revocable (adj.)
late 15c., from Old French revocable or directly from Latin revocabilis "that may be revoked," from revocare (see revoke). Alternative revokable attested from 1580s.
revocation (n.)
early 15c., from Old French revocacion or directly from Latin revocationem (nominative revocatio) "a calling back, recalling," noun of action from past participle stem of revocare (see revoke).
revoke (v.)
mid-14c., from Old French revoquer (13c.), from Latin revocare "rescind, call back," from re- "back" (see re-) + vocare "to call" (see voice (n.)). Related: Revoked; revoking.
revolt (v.)
1540s, from Middle French revolter (15c.), from Italian rivoltare "to overthrow, overturn," from Vulgar Latin *revolvitare "to overturn, overthrow," frequentative of Latin revolvere (past participle revolutus) "turn, roll back" (see revolve). Related: Revolted; revolting.
revolt (n.)
1550s, from Middle French révolte (c.1500), back formation from revolter (see revolt (v.)), or else from Italian rivolta.
revolting (adj.)
1590s, "that revolts, given to revolt, rebellious," present participle adjective from revolt (v.). Sense of "repulsive" is from 1806. Related: Revoltingly.
revolution (n.)
late 14c., originally of celestial bodies, from Old French revolucion "course, revolution (of celestial bodies)" (13c.), or directly from Late Latin revolutionem (nominative revolutio) "a revolving," noun of action from past participle stem of Latin revolvere "turn, roll back" (see revolve).

General sense of "instance of great change in affairs" is recorded from mid-15c. Political meaning "overthrow of an established political system" first recorded c.1600, derived from French, and was especially applied to the expulsion of the Stuart dynasty under James II in 1688 and transfer of sovereignty to William and Mary.
revolutionary (adj.)
1774; see revolution + -ary. As a noun, from 1850 (cf revolutionist).
revolutionist (n.)
1710; see revolution + -ist.
revolutionize (v.)
1797, "to cause to undergo a (political) revolution;" see revolution + -ize. Transferred sense of "to change a thing completely and fundamentally" is first recorded 1799. Related: Revolutionized; revolutionizing.
revolve (v.)
late 14c., "to change direction, bend around, turn (the eyes) back," from Old French revolver and directly from Latin revolvere "roll back, unroll, unwind; happen again, return; go over, repeat," from re- "back, again" (see re-) + volvere "to roll" (see volvox). In 15c., "to turn over (in the mind or heart), meditate." Meaning "travel around a central point" first recorded 1660s (earlier "cause to travel in an orbit around a central point," mid-15c.). Related: Revolved; revolving.
revolver (n.)
type of pistol, 1835, agent noun from revolve. So called by U.S. inventor Samuel Colt (1814-1862) for its revolving chamber cylinder.
revolving (adj.)
1690s, present participle adjective from revolve (v.). Revolving door attested from 1856 in industrial processes, 1896 in buildings.
revue (n.)
1872, "show presenting a review of current events," from French revue, from Middle French, literally "survey," noun use of fem. past participle of revoir "to see again" (see review (n.)). Later extended to shows consisting of a series of unrelated scenes.
revulsion (n.)
1540s, as a medical term, from Middle French revulsion (16c.) or directly from Latin revulsionem (nominative revulsio) "a tearing off, act of pulling away," noun of action from past participle stem of revellere "to pull away," from re- "away" (see re-) + vellere "to tear, pull," from PIE *wel-no-, suffixed form of root *wel- (4) "to tear, pull" (see svelte). The meaning "sudden reaction of disgust" is first attested 1816.
reward (n.)
mid-14c., "a regarding, heeding, observation," from Anglo-French and Old North French reward, back-formation from rewarder (see reward (v.)). Meaning "repayment for some service" is from late 14c. Sense of "sum of money in exchange for capture" is from 1590s.
reward (v.)
c.1300 "to grant, bestow;" early 14c. "to give as compensation," from Old North French rewarder "to regard, reward" (Old French regarder) "take notice of, regard, watch over," from re-, intensive prefix (see re-), + warder "look, heed, watch," from Germanic (see warder). Originally any form of requital. A doublet of regard. Related: Rewarded; rewarding.
rewind (v.)
also re-wind, 1717, from re- "back, again" + wind (v.1). Noun meaning "mechanism for rewinding film or tape" is recorded from 1938. Related: Rewound; rewinding.
reword (v.)
"to express in other words," c.1600, from re- "back, again" + word (v.). Related: Reworded; rewording.
rework (v.)
1842, from re- + work (v.). Related: Reworked; reworking.
rewrite (v.)
"to write again," 1560s, from re- "back, again" + write (v.). Related: Rewrote; rewritten; rewriting. Journalistic rewrite man is recorded from 1901. As a noun from 1926.
rex (n.)
"a king," 1610s, from Latin rex (genitive regis) "a king," related to regere "to keep straight, guide, lead, rule," from PIE root *reg- "to rule, to lead straight, to put right" (cognates: Sanskrit raj- "king;" Old Irish ri "king," genitive rig; see regal).
Reykjavik
capital of Iceland, literally "bay of smoke," from Old Norse reykja "to smoke" (see reek (n.)) + vik "bay" (see viking). So called from the natural hot springs there. Settlement said to date from 9c., but not established as a town until 1786.
Reynard (n.)
quasi-proper name for a fox, c.1300, from Old French Renart, Reynard name of the fox in Roman de Renart, from Old High German personal name Reginhart "strong in counsel," literally "counsel-brave." The first element is related to reckon, the second to hard. The tales were so popular that the name became the word for "fox" in Old French. Old French also had renardie "craftiness."
Reynold
masc. proper name, from Old French Reinald (Modern French Renaut, Latinized as Reginaldus), a popular name among the Normans, from Old High German Reginald, the first element related to reckon, the second to Old English wealdan "to rule" (see wield). Related: Reynolds.
RFD
also R.F.D.; 1882, American English, it stands for rural free delivery.
Rh factor
1942, from the first letters of rhesus; so called because the blood group, and its effects, were discovered in the blood of rhesus monkeys (1941).