Online Etymology Dictionary

retainer (n.2): "servant," 1530s, agent noun from retain (v.). Meaning "dental structure used to hold a bridge in place" is recorded from 1887.
retake (v.): mid-15c., "to take back," from re- "back, again" + take (v.). Meaning "to recapture" is recorded from 1640s; sense of "to record a second time" is attested from 1962. Related: Retook; retaking; retaken.
retaliate (v.): 1610s, from past participle stem of Latin retaliare (see retaliation). Related: Retaliated; retaliating.
retaliation (n.): 1580s, from Late Latin retaliare "pay back in kind," from re- "back" (see re-) + Latin talio "exaction of payment in kind," from talis "suchlike" (see that). Originally used both in good and evil senses.
retaliatory (adj.): 1813; see retaliate + -ory.
retard (v.): late 15c., from French retarder (13c.), from Latin retardare (see retardation). Related: Retarded; retarding. The noun is recorded from 1788 in the sense "retardation, delay;" from 1970 in offensive meaning "retarded person," originally American English, with accent on first syllable.
retardant (adj.): 1640s; see retard + -ant. From 1952 as a noun, "retardant substance."
retardation (n.): early 15c., "fact or action of making slower in movement or time," from Latin retardationem, noun of action from past participle stem of retardare "to make slow, delay, keep back, hinder," from re-, intensive prefix, + tardare "to slow" (see tardy).
retarded (adj.): 1810, past participle adjective from retard (v.). In childhood development sense, "mentally slow," attested from 1895 (cf. Italian tardivi).
retch (v.): 1540s, originally "to clear the throat, to cough up phlegm," from Old English hræcan "to cough up, spit" (related to hraca "phlegm"), from Proto-Germanic *khrækijanan (cf. Old High German rahhison "to clear one's throat"), of imitative origin (cf. Lithuanian kregeti "to grunt"). Meaning "to make efforts to vomit" is from 1850; sense of "to vomit" is first attested 1888. Related: Retched; retching.
rete (n.): late 14c., from Latin rete "net" (see reticulate). Plural is retia.
retell (v.): 1590s, from re- "back, again" + tell (v.). Related: Retold; retelling.
retention (n.): c.1400, from Latin retentionem (nominative retentio) "a retaining, a holding back," from past participle stem of retinere (see retain).
retentive (adj.): late 14c., from Old French retentif, from Latin past participle stem of retinere (see retain).
rethink (v.): 1700, from re- "back, again" + think (v.). Related: Rethinking.
reticence (n.): c.1600, from French réticence, from Latin reticentia "silence," from reticere "keep silent," from re-, intensive prefix, + tacere "be silent" (see tacit). "Not in common use until after 1830" [OED].
reticent (adj.): 1834, from Latin reticentem, present participle of reticere (see reticence).
reticle (n.): 1650s, from Latin reticulum, diminutive of rete "net" (see reticulate).
reticular (adj.): 1590s, from Modern Latin reticularis, from reticulum (see reticulate).
reticulate (adj.): 1650s, from Latin reticulatus "having a net-like pattern," from reticulum "little net," diminutive of rete "net," which probably is cognate with Lithuanian retis "sieve," and from either the root of Latin rarus "thin" or another PIE root meaning "twist, bind."
reticulation (n.): 1670s, noun of action or state from reticulate (adj.), from Latin reticulatus, from reticulum (see reticulate).
reticule (n.): "a ladies' small bag," 1801, from French réticule, from Latin reticulum (see reticulate).
reticulum (n.): 1650s, "second stomach of a ruminant," from Latin reticulum (see reticulate). Later given various uses in biology, cytology, histology, etc.
retina (n.): late 14c., from Medieval Latin retina, probably from Vulgar Latin (tunica) *retina, literally "net-like tunic," on resemblance to the network of blood vessels at the back of the eye, and ultimately from Latin rete "net" (see reticulate). The Vulgar Latin phrase may be Gerard of Cremona's 12c. translation of Arabic (tabaqa) shabakiyyah "netlike (layer)," itself probably a translation of Greek amphiblestroeides (khiton).
retinal (adj.): 1838; see retina + -al (1).
retinue (n.): late 14c., from Old French retenue "group of followers, state of service," literally "that which is retained," from fem. past participle of retenir "to employ, to retain, hold back" (see retain).
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). Meaning "to withdraw to some place for the sake of seclusion" 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. Baseball sense of "to put out" is recorded from 1874. Related: Retired; retiring.
retiree (n.): 1945, from retire + -ee.
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.