Online Etymology Dictionary

recount (n.): "a new count" (especially in an election), 1855, American English, from re- + count (n).
recount (v.2): "to enumerate again," 1764, from re- + count (v). Related: Recounted; recounting.
recoup (v.): 1620s, from French recouper "to cut back" (12c.), from Old French re- "back" (see re-) + couper "to cut," from coup "a blow" (see coup). Originally a legal term meaning "to deduct;" sense of "recompense for loss or expense" first recorded 1660s. Related: Recouped; recouping.
recourse (n.): late 14c., from Old French recours (13c.), from Latin recursus "return, retreat," literally "a running back," from stem of past participle of recurrere "run back, return" (see recur).
recover (v.): c.1300, "to regain consciousness," from Anglo-French rekeverer (late 13c.), Old French recovrer, from Latin recuperare "to recover" (see recuperation). Meaning "to regain health or strength" is from early 14c.; sense of "to get (anything) back" is first attested mid-14c. Related: Recovered; recovering.
recovery (n.): late 14c., Anglo-French recoverie (c.1300) or Old French recovree, from past participle of recovrer (see recover).
recreant (adj.): c.1300, "confessing oneself to be overcome or vanquished," from Old French recreant "yielding, giving," present participle of recroire "to yield in a trial by combat, surrender allegiance," perhaps on notion of "take back one's pledge, yield one's cause," from re- "again, back" (see re-) + croire "entrust, believe," from Latin credere (see credo).
Non sufficit ... nisi dicat illud verbum odiosum, quod recreantus sit. [Bracton, c.1260]
Meaning "unfaithful to duty" is from 1640s. Noun sense of "one who yields in combat, coward, faint-hearted person" is first recorded c.1400.
recreate (v.): "to create anew," 1580s, from re- "back, again" + create. Related: Recreated; recreating.
recreation (n.): late 14c., "refreshment or curing of a person, refreshment by eating," from Old French recreacion (13c.), from Latin recreationem (nominative recreatio) "recovery from illness," noun of action from past participle stem of recreare "to refresh, restore," from re- "again" (see re-) + creare (see create). Meaning "refresh oneself by some amusement" is first recorded c.1400; abbreviated form rec is attested from 1929. Verb recreate "to refresh by physical influence" is attested from c.1560, but not now used, probably from confusion with recreate.
recreational (adj.): 1650s, from recreation + -al (1). Related: Recreationally.
recriminate (v.): c.1600, from Medieval Latin recriminatus, past participle of recriminari "to make charges against," from Latin re- "back, again" (see re-) + criminari "to accuse," from crimen (genitive criminis) "a charge" (see crime). Related: Recriminated; recriminating.
recrimination (n.): 1610s, from French récrimination, from Medieval Latin recriminationem, from recriminari (see recriminate).
recrudesce (v.): 1875, back-formation from recrudescence, or else from Latin recrudescere, from re- (see re-) + crudescere, from crudus "raw" (see crude). Related: Recrudesced; recrudescing.
recrudescence (n.): 1721, from Latin recrudescere "re-open" (of wounds), literally "become raw again," from re- "again" (see re-) + crudescere, from crudus "raw" (see crude) + inchoative suffix -escere.
recruit (v.): 1630s, "to strengthen, reinforce," from French recruter (17c.), from recrute, Picardy dialect variant of recrue "levy," literally "new growth," from Old French recreu, past participle of recreistre "grow or increase again," from re- "again" (see re-) + creistre "to grow," from Latin crescere "to grow" (see crescent). "The French word first appeared in literary use in gazettes published in Holland, and was disapproved of by French writers in the latter part of the 17th c." [OED]. Sense of "to enlist new soldiers" is attested from 1650s; of student athletes, from 1913. Related: Recruited; recruiting.
recruit (n.): "military reinforcement, one of a newly raised body of troops," 1650s, from recruit (v)., replacing earlier recrew, recrue.
recruitment (n.): 1795, from recruit (v.) + -ment.
recrystallization (n.): 1793, from re- + crystallization.
rectal (adj.): 1822; see rectum + -al (1).
rectangle (n.): 1570s, from Middle French rectangle, from rect-, comb. form of Latin rectus "right" (see right (adj.1)) + Old French angle (see angle). Medieval Latin rectangulum meant "a triangle having a right angle" (7c.).
rectangular (adj.): 1620s; see rectangle + -ar.
rectification (n.): late 14c., from Old French rectificacion (14c.) or directly from Late Latin rectificationem (nominative rectificatio), noun of action from past participle stem of rectificare (see rectify).
rectifier (n.): 1610s, agent noun from rectify.
rectify (v.): c.1400, from Old French rectifier, literally "to make straight" (14c.), from Late Latin rectificare "make right" (3c.), from Latin rectus "straight" (see right (adj.1)) + root of facere "to make" (see factitious). Related: Rectified; rectifying.
rectilinear (adj.): "forming a straight line," 1650s, from rectiline (1560s), from Late Latin rectilineus, from rectus "straight" (see right (adj.1)) + linea "line" (see line (n.)).
rectitude (n.): early 15c., "quality of being straight," from Middle French rectitude (14c.), from Late Latin rectitudinem (nominative rectitudo) "straightness, uprightness," from Latin rectus "straight" (see right (adj.1)). Sense of "upright in conduct or character" is from 1530s.
recto-: word-forming element, before vowels rect-, from comb. form of rectum.
rector (n.): late 14c., from Latin rector "ruler, governor, guide," from rect-, past participle stem of regere "to rule, guide" (see regal). Used originally of Roman governors and God, by 18c. generally restricted to clergymen and college heads.
rectory (n.): 1530s, from French rectorie (14c.) or Medieval Latin rectoria, from rector (see rector). Originally "benefice held by a rector;" of his residence, from 1849.
rectum (n.): early 15c., from Latin intestinum rectum "straight intestine," in contrast to the convolution of the rest of the bowels, from neuter past participle of regere "to straighten" (see regal). A loan-translation of Greek apeuthysmeon enteron, "the name given to the lowest part of the large intestine by Galen, who so called it because he dissected only animals whose rectum (in contradistinction to that of man) is really straight" [Klein].
recumbent (adj.): 1640s (implied in recumbency), from Latin recumbentem (nominative recumbens), present participle of recumbere "to recline," from re- "back" (see re-) + -cumbere "to lie down," related to cubare "be lying" (see cubicle). A verb, recumb, has been attempted in English occasionally since 1670s.
recuperate (v.): 1540s, from Latin recuperatus, past participle of recuperare (see recuperation). Meaning "to recover from sickness or loss" is from 1864. Related: Recuperated; recuperating.
recuperation (n.): late 15c., "recovery or regaining of things," from Latin recuperationem (nominative recuperatio), from past participle stem of recuperare "recover," related to recipere (see receive). Meaning "restoration to health or vigor" is from 1865.
recur (v.): mid-15c., from Latin recurrere "to return, come back," from re- "back, again" (see re-) + currere "to run" (see current (adj.)). Originally of persons; application to thoughts, ideas, etc. is recorded from 1704. Related: Recurred; recurring.
recurrence (n.): 1640s; see recurrent + -ence.
recurrent (adj.): 1610s, from Latin recurrentem, present participle of recurrere (see recur).
recurring (adj.): 1711, present participle adjective from recur.
recursion (n.): 1610s, from Latin recursionem, noun of action from past participle stem of recurrere (see recur).
recursive (adj.): 1790, from Latin recurs-, stem of recurrere (see recur) + -ive. Mathematical sense is from 1934. Related: Recursively.
recusal (n.): 1911; from recuse + -al (2).
recusant: 1550s, from Latin recusantem, present participle of recusare (see recuse).
recuse (v.): late 14c., "to reject another's authority as prejudiced," from Old French recuser (13c.), from Latin recusare "to refuse, make an objection," from re- (see re-) + causa (see cause). The word now is used mostly reflectively. Related: Recused; recusing.
recyclable (adj.): 1971, from recycle + -able. As a noun, by 1973. Related: Recyclables.
recycle (v.): 1922, originally of industrial processes; see re- + cycle (v.). Specifically of waste material from 1960. Related: Recycled; recycling.
recycling (n.): 1924, verbal noun from recycle (v.). Originally a technical term in oil-refining and similar industries; its broader consumer sense dates from 1960.
red (1): Old English read, from Proto-Germanic *rauthaz (cf. Old Norse rauðr, Danish rød, Old Frisian rad, Middle Dutch root, German rot, Gothic rauþs), from PIE root *reudh- (cf. Latin ruber, also dialectal rufus "light red," mostly of hair; Greek erythros; Sanskrit rudhira-; Avestan raoidita-; Old Church Slavonic rudru, Polish rumiany, Russian rumjanyj "flushed, red," of complexions, etc.; Lithuanian raudas; Old Irish ruad, Welsh rhudd, Breton ruz "red"). The only color for which a definite common PIE root word has been found. The surname Read/Reid retains the original Old English long vowel pronunciation. The initial -e- in the Greek word is because Greek tends to avoid beginning words with -r-.

The color as characteristic of "British possessions" on a map is attested from 1885. The red flag was used as a symbol of defiance in battle on land or sea from c.1600. To see red "get angry" is an American English expression first recorded 1898. Red light as a sign to stop is from 1849, long before traffic signals. As the sign of a brothel, it is attested from 1899. As a children's game (in reference to the traffic light meaning) it is recorded from 1953. Red-letter day (late 14c.) was originally a saint's day, marked on church calendars in red letters. Red ball signifying "express" in railroad jargon is 1904, originally (1899) a system of moving and tracking freight cars. Red-blooded "vigorous, spirited" is recorded from 1877. Red dog, type of U.S. football pass rush, is recorded from 1959. Red shift in spectography is first recorded 1923. Red carpet "sumptuous welcome" is from 1934, but the custom for dignitaries is described as far back as Aeschylus (e.g. "Agamemnon").
red (2): "Bolshevik," 1917, from red (1), the color they adopted for themselves. Association in Europe of red with revolutionary politics (on notion of blood and violence) is from at least 1297, but got a boost 1793 with adoption of the red Phrygian cap (French bonnet rouge) as symbol of the French Revolution. First specific political reference in English was 1848 (adj.), in news reports of the Second French Republic (a.k.a. Red Republic). The noun meaning "radical, communist" is from 1851.
red cent (n.): obsolete type of copper penny, first recorded 1839, American English ("red" has been the color of copper since ancient times).
Red Cross: early 15c., "national emblem of England" (St. George's Cross); in 17c., a red cross was the mark placed on the doors of London houses inflected with the plague. Red cross (in Muslim lands, red crescent) adopted as a symbol of ambulance service 1864 by the Geneva Conference.
red herring (n.): "smoked herring" early 15c. (they turn red when cured), as opposed to white herring "fresh herring." Supposedly used by fugitives to put bloodhounds off their scent (1680s), hence metaphoric sense (1864) of "something used to divert attention from the basic issue;" earlier simply "a false lead":
Though I have not the honour of being one of those sagacious country gentlemen, who have so long vociferated for the American war, who have so long run on the red-herring scent of American taxation before they found out there was no game on foot; [etc.] [Parliamentary speech dated March 20, 1782, reprinted in "Beauties of the British Senate," London, 1786]