Online Etymology Dictionary

retirement (n.): 1590s, "act of retreating," also "act of withdrawing into seclusion," from French retirement (1570s); see retire + -ment. Meaning "privacy" is from c.1600; that of "withdrawal from occupation or business" is from 1640s.
retool (v.): 1866, "to shape again with a tool," from re- "back, again" + tool (v.). Meaning "to furnish a factory with new equipment" is recorded from 1940. Related: Retooled; retooling.
retort (v.): 1550s, from Latin retortus, past participle of retorquere "turn back," from re- "back" (see re-) + torquere "to twist" (see thwart). Related: Retorted; retorting. The noun is c.1600, from the verb.
retouch (v.): 1640s, from French retoucher (13c.) "to touch again" (with a view to improving)," from re- "again" (see re-) + toucher (see touch (v.)).
retrace (v.): 1690s, from French retracer "to trace again," from Middle French retracier, from re- "again" (see re-) + tracier "to trace" (see trace).
retract (v.): early 15c., "to draw (something) back," from Latin retractus, past participle of retrahere (see retraction). Sense of "to revoke, withdraw" is attested from 1540s. Related: Retracted; retracting.
retractable (adj.): "capable of being drawn in," 1769; see retract + -able. Meaning "capable of being disowned" is recorded from 1610s.
retraction (n.): late 14c., from Latin retractionem (nominative retractio), from past participle stem of retractare "revoke, cancel," from re- "back" (see re-) + tractere "draw violently," frequentative of trahere "to draw" (see tract (n.1)). Originally the title of a book by St. Augustine, correcting his former writings. Meaning "recantation of opinion with admission of error" is from 1540s.
retrain (v.): 1905, from re- "back, again" + train (v.). Related: Retrained; retraining.
retread (v.): "to put a new tread on (a tire)," 1908, from re- "back, again" (see re-) + tread (q.v.). The noun is attested from 1914; in World War I it was Australian slang for "a re-enlisted soldier."
retreat (n.): c.1300, from Old French retret, noun use of past participle of retrere "draw back," from Latin retrahere "draw back," from re- "back" (see re-) + trahere "to draw" (see tract (n.1)). Meaning "place of seclusion" is from early 15c.; sense of "establishment for mentally ill persons" is from 1797.
retreat (v.): early 15c., "to draw in, draw back, leave the extremities," from Old French retret, past participle of retrere (see retreat (n.)). Meaning "to fall back from battle" is mid-15c. Related: Retreated; retreating.
retrench (v.): 1590s, "dig a new trench as a second line of defense," from French retrencher "to cut off," from re- "back" (see re-) + Old French trenchier "to cut." Sense of "cut down, reduce (expenses, etc.)" is from 1620s.
retrenchment (n.): c.1600, from French retrenchement "a cutting off or out," from retrencher (see retrench). Military sense is recorded from 1580s; see trench.
retribute: 1570s, from Latin retributus, past participle of retribuere (see retribution).
retribution (n.): late 14c., "repayment," from Latin retributionem (nominative retributio) "recompense, repayment," from retributus, past participle of retribuere "hand back, repay," from re- "back" (see re-) + tribuere "to assign, allot" (see tribute). Sense of "evil given for evil done" is from day of retribution (1520s) in Christian theology, the time of divine reward or punishment.
retributive (adj.): 1670s; see retribute + -ive.
retrieval (n.): 1640s; see retrieve + -al (2).
retrieve (v.): early 15c., retreve, from Middle French retruev-, stem of Old French retrouver "find again," from re- "again" (see re-) + trouver "to find," probably from Vulgar Latin *tropare "to compose" (see trove). Altered 16c. to retrive; modern form is from c.1650.
retriever (n.): "dog used for retrieving game," late 15c., agent noun from retrieve.
retro: 1974, from French rétro (1973), short for rétrograde, supposedly first used of a revival c.1968 of Eva Peron-inspired fashions (see retrograde). There is an isolated use in English from 1768.
retro-: prefix meaning "backwards, behind," from Latin retro (prep.) "backward, back, behind," probably originally the ablative form of *reteros, based on re- "back" (see re-). Common in combinations in post-classical Latin.
retroactive (adj.): 1610s, from French rétroactif (fem. rétroactive) "casting or relating back," from Latin retroactus, past participle of retroagere "drive or turn back," from retro- "back" (see retro-) + agere "to drive, set in motion" (see act).
retrofit: 1954, from retro(active) + (re)fit.
retroflex (adj.): 1776; , from Modern Latin retroflexus, past participle of retroflectere, from retro- (see retro-) + flectere "to bend" (see flexible). The verb (1898) is a back-formation from retroflexed (1806), from the adjective.
retrograde (adj.): late 14c., originally of the apparent motions of planets, from Latin retrogradus "going backward," from retrogradi "move backward," from retro- "backward" (see retro-) + gradi "to go, step" (see grade (n.)). General sense of "tending to revert" is recorded from 1530s.
retrogress (v.): 1819, from Latin retrogress-, past participle stem of retrogradi (see retrograde).
retrogression (n.): 1640s, formed on model of progression from Latin retrogressus, past participle of retrogradi "move backward" (see retrograde).
retrogressive (adj.): 1817; see retrogress + -ive. Related: Retrogressively.
retrospect: c.1600, from Latin retrospectum, past participle of retrospicere "look back," from retro- "back" (see retro-) + specere "look at" (see scope (n.1)).
retrospection (n.): 1630s, noun of action from Latin retrospicere (see retrospect).
retrospective (adj.): 1660s, from retrospect + -ive. As a noun, from 1964, short for retrospective exhibition (1919), etc. Related: Retrospectively.
retrovirus (n.): 1977, earlier retravirus (1974), from re(verse) tra(nscriptase) + virus. So called because it contains reverse transcriptase, an enzyme that uses RNA instead of DNA to encode genetic information, which reverses the usual pattern. Remodeled by influence of retro- "backwards."
return (v.): mid-14c., "to come back," from Old French retorner "turn back, return," from re- "back" (see re-) + torner "to turn" (see turn (v.)). Transitive sense is attested from early 15c. Related: Returned; returning.
return (n.): late 14c., "act of coming back," from Old French retorne from retorner (see return (v.)). In the tennis sense, it is from 1886. Meaning "official report of election results" is attested from mid-15c. Meaning "a yield, a profit" is recorded from 1620s. Many happy returns of the day was used by Addison, 1716.
Reuben: masc. proper name, Old Testament eldest son of Jacob and name of the tribe descended from him, from Greek Rouben, from Hebrew Reubhen, probably literally "Behold a son," from reu, imper. of ra'ah "he saw" + ben "a son." The reuben sandwich (1956) is "not obviously connected" with the sense in rube [OED].
reunification (n.): 1880; see re- + unification.
reunion (n.): c.1600, from re- "back, again" + union. Cf. French réunion (1540s). The island of Reunion, formerly known as Bourbon, was renamed during the French Revolution (1793) in commemoration of the 1792 union of revolutionaries from Marseille with the National Guard in Paris, renamed back to Bourbon after 1815, then back to the current name after 1848.
reunite (v.): 1590s, from adj. reunit "reunited" (mid-15c.), from Medieval Latin reunitus, past participle of reunire "unite again," from Latin re- "again" (see re-) + unire "join together" (see unite). Related: Reunited; reuniting.
reupholster (v.): 1935, see re- + upholster.
reuptake: by 1977; see re- + uptake.
reusable (adj.): 1959, first attested in a Sears, Roebuck & Co. catalogue (in reference to plastic bags for paper plates), from re- "back, again" + usable (see use (v.)).
reuse: 1843 (v.); 1866 (n.); see re- + use. Related: Reused; reusing.
Reuters: news service begun in London 1851 by Baron Paul Julius von Reuter (1816-1899), founder of a telegraph office and pigeon post bureau in Aachen in 1849.
rev (v.): 1916, from earlier noun (1901), shortening of revolution, in reference to the internal combustion engine. Related: Revved; revving.
revaluate (v.): 1949, back-formation from revaluation.
revaluation (n.): 1610s; see re- + valuation.
revamp (v.): 1850, from re- "again" + vamp "patch up, replace the upper front part of a shoe" (see vamp (v.)). An earlier verb was new-vamp (1630s).
revanche: 1858, from French revanche (see revanchist).
revanchist (n.): "one seeking to avenge Germany's defeat in World War I and recover lost territory," 1926 (on model of French revanchiste), from revanche "revenge, requital" (1858), especially in reference to a national policy seeking return of lost territory, from French revanche, literally "revenge," from Middle French revenche, back-formation from revenchier (see revenge).