retinal (adj.)
1838; see retina + -al (1).
retinitis (n.)
1821, from retina + -itis.
retinue (n.)
late 14c., from Old French retenue "group of followers, state of service," literally "that which is retained," noun use of fem. past participle of retenir "to employ, to retain, hold back" (see retain). Related: Retinular.
retiracy (n.)
1824, American English, irregularly from retire on model of privacy.
retire (v.)
1530s, of armies, "to retreat," from Middle French retirer "to withdraw (something)," from re- "back" (see re-) + Old French tirer "to draw" (see tirade). Related: Retired; retiring.

Meaning "to withdraw" to some place, especially for the sake of privacy, is recorded from 1530s; sense of "leave an occupation" first attested 1640s (implied in retirement). Meaning "to leave company and go to bed" is from 1660s. Transitive sense is from 1540s, originally "withdraw, lead back" (troops, etc.); meaning "to remove from active service" is from 1680s. Baseball sense of "to put out" is recorded from 1874.
retired (adj.)
1580s, "separated from society or public notice," past participle adjective from retire (v.). Meaning "having given up business" is from 1824. Abbreviation ret'd. attested from 1942.
retiree (n.)
1945, from retire + -ee.
retirement (n.)
1590s, "act of retreating," also "act of withdrawing into seclusion," from Middle French retirement (1570s); see retire + -ment. Meaning "privacy" is from c.1600; that of "withdrawal from occupation or business" is from 1640s.
retiring (adj.)
1580s, "departing, retreating," present participle adjective from retire (v.). Also "fond of retiring, disposed to seclusion," hence "unobtrusive, modest, subdued" (1766).
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, "make return in kind" (especially of an injury), from Old French retort and directly from Latin retortus, past participle of retorquere "turn back, twist back, throw back," from re- "back" (see re-) + torquere "to twist" (see torque (n.)). Applied to exchanges of jest or sarcasm by c.1600, hence "say or utter sharply and aggressively in reply" (1620s). Related: Retorted; retorting.
retort (n.1)
"act of retorting," c.1600, from retort (v.).
retort (n.2)
"vessel used in chemistry for distilling or effecting decomposition by the aid of heat," c.1600, from Middle French retorte, from Medieval Latin *retorta "a retort, a vessel with a bent neck," literally "a thing bent or twisted," from past participle stem of Latin retorquere (see retort (v.)).
retortion (n.)
1590s, from Medieval Latin retortionem (nominative retortio), noun of action from past participle stem of Latin retorquere (see retort (v.)).
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 (v.)). Related: Retraced; retracing.
retract (v.)
early 15c., "to draw (something) back," from Old French retracter (14c.) and directly from Latin retractus, past participle of retrahere "to draw back" (see retraction). Sense of "to revoke, recant, take back" is attested from 1540s, probably a back-formation from retraction. Related: Retracted; retracting.
retractable (adj.)
"capable of being drawn in," 1769; see retract + -able. Meaning "capable of being disowned" is recorded from 1610s. Also sometimes spelled retractible.
retraction (n.)
late 14c., "withdrawal of an opinion," from Latin retractionem (nominative retractio) "a drawing back, hesitation, refusal," noun of action 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.
retransmission (n.)
1788, from re- + transmission.
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, "a step backward;" late 14c., "act of retiring or withdrawing; military signal for retiring from action or exercise," from Old French retret, noun use of past participle of retrere "draw back," from Latin retrahere "draw back, withdraw, call 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. Meaning "period of retirement for religious self-examination" is from 1756.
retreat (v.)
early 15c., "to draw in, draw back, leave the extremities," from retreat (n.) and in part from Old French retret, past participle of retrere. Meaning "to fall back from battle" is mid-15c. Related: Retreated; retreating.
retrench (v.1)
1590s, "dig a new trench as a second line of defense," 1590s, probably a back-formation from retrenchment in the military sense. Related: Retrenched; retrenching.
retrench (v.2)
"cut off, cut down, pare away" (expenses, etc.), 1620s, from obsolete French retrencher "to cut off, lessen, shorten" (Modern French retrancher, Old French retrenchier), from re- "back" (see re-) + Old French trenchier "to cut" (see trench). Related: Retrenched; retrenching.
retrenchment (n.)
"action of lopping off or pruning," c.1600, from obsolete French retrenchement "a cutting off or out," from retrencher (see retrench (v.2)). Military sense is recorded from 1580s; see retrench (v.1).
retrial (n.)
1813, from re- + trial (n.).
retribute (v.)
"give in return," 1570s, from Latin retributus, past participle of retribuere "give back, restore, repay" (see retribution). Related: Retributed; retributing.
retribution (n.)
late 14c., "repayment," from Old French retribution and directly from Latin retributionem (nominative retributio) "recompense, repayment," noun of action from past participle stem of retribuere "hand back, repay," from re- "back" (see re-) + tribuere "to assign, allot" (see tribute). Originally "that which is given in return for past good or evil;" restricted modern use of "evil given for evil done" (1560s) is from day of retribution (1520s), in Christian theology the time of divine reward or punishment.
retributive (adj.)
1670s, from retribute + -ive.
retrievable (adj.)
1711, from retrieve + -able.
retrieval (n.)
1640s, from retrieve + -al (2).
retrieve (v.)
early 15c., retreve, originally in reference to dogs finding lost game, from Middle French retruev-, stem of Old French retreuver (Modern French retrouver) "find again, recover, meet again, recognize," 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 mid-17c.
retriever (n.)
"dog used for retrieving game," late 15c., agent noun from retrieve.
retro (adj.)
1974, from French rétro (1973), supposedly first used of a revival c.1968 of Eva Peron-inspired fashions and short for rétrograde (see retrograde). There is an isolated use in English from 1768, and the word apparently was used in 19c. French as a term in billiards. As a noun, short for retro-rocket (1948) from 1961.
retro-
word-forming element meaning "backwards; behind," from Latin retro (prep.) "backward, back, behind," also of time, "formerly, in past times," probably originally the ablative form of *reteros, based on re- "back" (see re-).
L. retro stands to re- as intro, "in, within"; to in, "in," and as citro, "hither," stands to cis, "on this side." [Klein]
Common in combinations in post-classical Latin (the classical equivalent was post-). Active in English as a word-forming element from mid-20c.
retroactive (adj.)
1610s, from French rétroactif (16c.) "casting or relating back," from Latin retroact-, past participle stem of retroagere "drive or turn back," from retro- "back" (see retro-) + agere "to drive, set in motion" (see act (v.)). Related: Retroactively.
retrocopulation (n.)
"copulation from behind," 1640s, from retro- + copulation. Related: Retrocopulate (v.).
retrofit (v.)
1954, from retro- + fit (v.). Related: Retrofitted; retrofitting. As a noun, 1956, from the verb.
retroflex (adj.)
1776, from Modern Latin retroflexus, past participle of retroflectere "to bend back," 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 back, 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.)
"move backward; deteriorate," 1816, probably a back-formation from retrogression. Related: Retrogressed; retrogressing.
retrogression (n.)
1640s, noun of action, formed on model of progression, from Latin retrogressus, past participle of retrogradi "move backward" (see retrograde).
retrogressive (adj.)
"tending to move backward," 1785, from Latin retrogress-, past participle stem of retrogradi "move backward, go backward" (see retrograde) + -ive. Related: Retrogressively.
retrospect (n.)
c.1600, "a regard or reference" (to something), from Latin retrospectum, past participle of retrospicere "look back," from retro- "back" (see retro-) + specere "look at" (see scope (n.1)). Meaning "survey of past events" is from 1660s.
retrospection (n.)
1630s, noun of action from past participle stem of Latin retrospicere (see retrospect).
retrospective (adj.)
1660s, from retrospect + -ive. As a noun, from 1964, short for retrospective exhibition (1908), etc. Related: Retrospectively.
retrousse (adj.)
"turned up" (of the nose), 1802, from French retroussé (16c.) past participle adjective from retrousser "to turn up."
retroversion (n.)
1580s, "a tilting or turning backward," noun of action or state from Latin retroversus "turned or bent backwards," from retro (see retro-) + versus "turned" (see versus).