Online Etymology Dictionary

refraction (n.) $Look up refraction at Dictionary.com$: 1570s, from Late Latin refractionem (nominative refractio) "a breaking up," noun of action from past participle stem of Latin refringere "to break up," from re- "back" (see re-) + comb. form of frangere "to break" (see fraction). Refrangible first recorded 1670s.
refractive (adj.) $Look up refractive at Dictionary.com$: 1670s, from Late Latin refractivus, or from refract + -ive.
refractory (adj.) $Look up refractory at Dictionary.com$: "stubborn, obstinate, perverse," 1610s (earlier refractorious, 1550s), from Latin refractarius "obstinate."
refrain (v.): c.1300, from Old French refraigner "restrain, repress" (12c.), from Latin refrenare "bridle, hold in with a bit," from re- "back" (see re-) + frenare "restrain, furnish with a bridle," from frenum "a bridle." Related: Refrained; refraining.
refrain (n.): late 14c., from Old French refrain, alteration of refrait, properly past participle of refraindre "repeat," also "break off," from Provençal refranhar "singing of birds, refrain," from Vulgar Latin *refrangere "break off," alteration of Latin refringere (see refraction). The notion is of something that causes a song to "break off" then resume. Not common before 19c.
reframe (v.): 1580s, from re- + frame (v.). Related: Reframed; reframing.
refresh (v.): late 14c., from Old French refrescher (12c.; Modern French rafraîchir), from re- "again" (see re-) + fresche "fresh" (Modern French frais), from a Germanic source (cf. Old High German frisc "fresh," see fresh (adj.)). Related: Refreshed; refreshing. Mental or spiritual sense of refreshing is attested from 1690s.
refreshment (n.): late 14c., "act or fact of refreshing," from Old French refreschement, from refrescher (see refresh). Refreshments, of food and drink only, from 1660s.
refried beans (n.): 1957, translating Spanish frijoles refritos.
refrigerant: 1590s (adj.); 1670s (n.); originally in medicine; see refrigerate + -ant.
refrigerate (v.): 1530s, from Latin refrigeratus, past participle of refrigerare (see refrigeration). Related: Refrigerated; refrigerating. Earlier words in the same sense of "to make cold, to cool" were infrigiden, infrigidate (both early 15c.).
refrigeration (n.): late 15c., "act of cooling or freezing," from Latin refrigerationem "mitigation of heat," especially in sickness, noun of action from refrigerare, from re- "again" (see re-) + frigerare "make cool," from frigus (genitive frigoris) "cold" (see frigid). Specifically of "freezing provisions as a means of preserving them" from 1881.
refrigerator (n.): "cabinet for keeping food cool," 1824, originally in the brewery trade, in place of earlier refrigeratory (c.1600). Agent noun from refrigerate. The electric-powered household device was available from c.1918.
reft: 1847, past participle of reave.
refuel (v.): also re-fuel, 1811, from re- "again" + fuel (v.). Originally in a spiritual sense. Related: Refueled; refueling.
refuge (n.): late 14c., from Old French refuge, from Latin refugium "a taking refuge, place to flee back to," from re- "back" (see re-) + fugere "to flee" (see fugitive) + -ium "place for."
refugee (n.): 1685, from French refugié, noun use of past participle of refugier "to take shelter, protect," from Old French refuge (see refuge). First applied to French Huguenots who migrated after the revocation (1685) of the Edict of Nantes. The word meant "one seeking asylum," till 1914, when it evolved to mean "one fleeing home" (first applied in this sense to civilians in Flanders heading west to escape fighting in World War I).
refulgent (adj.): c.1500, from Latin refulgentem (nominative refulgens), present participle of refulgere "flash back, shine brilliantly," from re- "back" (see re-) + fulgere "to shine" (see bleach (v.)).
refund (v.): "to give back, restore," early 15c. (earlier "to pour back," late 14c.), from Old French refunder "restore," from Latin refundere "give back, restore," literally "pour back," from re- "back" (see re-) + fundere "to pour" (see found (2)). Specifically of money from 1550s. Related: Refunded; refunding.
refund (n.): 1782, from refund (v.).
refurbish (v.): 1610s, from re- "again" + furbish, on model of French refourbir. Related: Refurbished; refurbishing.
refusal (n.): late 15c., from refuse + -al (2).
refuse (v.): c.1300, from Old French refuser (12c.), from Vulgar Latin *refusare, frequentative of past participle stem of Latin refundere "pour back, give back" (see refund). Related: Refused; refusing. Refusenik "Soviet Jew who has been refused permission to emigrate to Israel" (1975) is a partial translation of Russian otkaznik, from otkazat "to refuse."
refuse (n.): late 14c., "a rejected thing; waste material, trash," from Old French refus "waste product, rubbish," a back-formation from the past participle of refuser (see refuse (v.)). As an adjective from early 15c.
refutation (n.): 1540s, from Latin refutationem, noun of action from refutare (see refute).
refute (v.): 1510s, "refuse, reject," from Latin refutare "drive back, repress, repel, rebut," from re- "back" (see re-) + -futare "to beat," probably from PIE root *bhat- "to strike down" (cf. bat (n.1)). Meaning "prove wrong" dates from 1540s. Since c.1964 linguists have frowned on the subtle shift in meaning towards "to deny," as it is used in connection with allegation. Related: Refuted; refuting.
reg (n.): 1952 as a shortening of regulation.
regain (v.): 1540s, from Middle French regaigner, from re- "again" (see re-) + gaginer, from Old French gaaignier (see gain (v.)). Related: Regained; regaining.
regal (adj.): early 14c., from Latin regalis "royal, kingly, belonging to a king," from rex (genitive regis) "king," from PIE root *reg- "move in a straight line," hence, "direct, rule, guide" (cf. Sanskrit raj- "a king, a leader;" Avestan razeyeiti "directs;" Persian rahst "right, correct;" Latin regere "to rule," rex "a king, a leader," rectus "right, correct;" Old Irish ri, Gaelic righ "a king;" Gaulish -rix "a king," in personal names, e.g. Vircingetorix; Gothic reiks "a leader;" Old English rice "kingdom," -ric "king," rice "rich, powerful," riht "correct;" Gothic raihts, Old High German recht, Old Swedish reht, Old Norse rettr "correct").
regale (v.): 1650s, from French régaler "to entertain or feast," from Old French rigale, from gale "merriment," from galer "make merry" (see gallant). Influenced in Old French by se rigoler "amuse oneself, rejoice," of unknown origin. Italian regalo is from French. Related: Regaled; regaling.
regalia (n.): 1530s, "rights and powers of a king," from Latin regalia "royal things," from neuter plural of regalis (see regal). Meaning "decorations or insignia of an order" first recorded 1670s.
regard (n.): mid-14c., from Old French regard, from regarder "take notice of," from re-, intensive prefix + garder "look, heed" (see guard). Meanings "consideration, appearance, kindly feeling" all recorded late 14c.
regard (v.): early 15c., from Middle French regarder, from regard (see regard (n.)). Related: Regarded; regarding.
regardless (adj.): "indifferent," 1590s, from regard (n.) + -less. Eliptical for "regardless of consequences, expenses, etc.," from 1872.
regards (n.): plural of regard (q.v.). In letters, from 1775, from regard in the sense of "esteem, affection" (1590s).
regatta (n.): 1650s, name of a boat race among gondoliers held on the Grand Canal in Venice, from Italian (Venetian dialect) regatta, literally "contention for mastery," from regattare "to compete, haggle, sell at retail," possibly from recatare. The general meaning of "boat race, yacht race" is usually considered to have begun with a race on the Thames by that name June 23, 1775 (cf. OED), but there is evidence that it was used as early as 1768.
regency (n.): early 15c., from Medieval Latin regentia, from Latin regens (see regent). Notable instances were: France 1715-1723 (under Philip, Duke of Orleans), Britain 1811-1820 (under George, Prince of Wales, Prince Regent), "in each case with suggestion of debauchery" [Weekley]. In reference to the style of that time, attested from 1880 (there is an unexplained use in Jane Austen from 1793). Cf. French equivalent Régence, attested in English from 1919. U.S. Albany Regency refers to dominant political faction in New York state c.1820-1850.
regenerate: late 15c. (adj.); 1550s (v.), from Latin regeneratus, past participle of regenerare (see regeneration). Related: Regenerated; regenerating.
regeneration (n.): c.1300, from Late Latin regenerationem (nominative regeneratio) "a being born again," noun of action from past participle stem of Latin regenerare "make over, generate again," from re- "again" (see re-) + generare "to produce" (see generation). Specifically of animal tissue, 1540s; of forests, 1888.
regenerative (adj.): c.1400, from French régénératif or directly from Medieval Latin regenerativus, from regeneratus (see regeneration).
regent (n.): early 15c., from the adjective (which is attested from late 14c.), from Old French regent, from Medieval Latin regentem (nominative regens), from Latin regens "ruler, governor," also present participle of regere "to rule, direct" (see regal). Senses of "university faculty member" is attested from 1520s, originally Scottish.
reggae (n.): 1968, Jamaican English (first in song title "Do the Reggay" by Toots & the Maytals), perhaps related to rege-rege "a quarrel, protest," literally "ragged clothes," variant of raga-raga, alteration and reduplication of English rag (n.).
regicide (n.): 1540s, formed from Latin rex (genitive regis) "king" on model of suicide.
regime (n.): "system of government or rule," 1792, from French régime, from Latin regimen "rule, guidance, government," from regere (see regal). In French, l'ancien régime refers to the system of government before the revolution of 1789.
regimen (n.): mid-15c., "act of governing," from Old French regimen (14c.), from Latin regimen "rule, guidance, government," from regere "to rule" (see regal). Medical sense of "course of diet, exercise, etc. for sake of health" first recorded late 15c.
regiment (n.): late 14c., "government, rule, control," from Old French regiment "government, rule" (early 14c.), from Late Latin regimentum "rule, direction," from Latin regimen (see regimen). Meaning "unit of an army" first recorded 1570s (originally the reference was to permanent organization and discipline), from French.
regiment (v.): "to form into a regiment," 1610s, from regiment (n.). Related: Regimented; regimenting.
regimental (adj.): 1650s, from regiment (n.) + -al (1). As a noun, regimentals, "dress proper to a particular regiment, militaty uniform," is from 1742.
regimentation (n.): 1856, from regiment + -ation.
Regina: fem. proper name, from Latin, literally "queen;" related to rex (genitive regis) "king" (see regal). Cf. Sanskrit rajni "queen," Welsh rhyain "maiden, virgin."