Online Etymology Dictionary

relocation (n.): 1746, in Scottish law, "renewal of a lease," noun of action from relocate. Meaning "act of relocating" is from 1837.
reluctance (n.): 1640s, "act of struggling against," from obsolete verb reluct "to struggle or rebel against" (1520s), from Latin reluctari "to struggle against, resist, make opposition," from re- "against" (see re-) + luctari "to struggle, wrestle," perhaps shares a common origin with Greek lygos "pliant twig," lygizein "to bend, twist," Old English locc "twist of hair" (see lock (n.2)). Meaning "unwillingness" is first attested 1660s. Related: Reluctancy (1620s.).
reluctant (adj.): "unwilling," 1660s, from Latin reluctantem (nominative reluctans), present participle of reluctari (see reluctance). Related: Reluctantly. The Latin word is also the source of Spanish reluchante, Italian riluttante.
rely (v.): early 14c., "to gather, assemble" (transitive and intransitive), from Old French relier "assemble, put together; fasten, attach, rally, oblige," from Latin religare "fasten, bind fast," from re-, intensive prefix (see re-), + ligare "to bind" (see ligament). Sense of "depend, trust" is from 1570s, perhaps via notion of "rally to, fall back on." Typically used with on, perhaps by influence of lie (v.2). Related: Relied; relying.
rem (n.): "unit for measuring radiation," 1947, acronym of roentgen equivalent man.
remain (n.): "those left over or surviving," mid-15c., from Middle French remain, back-formation from Old French remanoir, remaindre, or else formed in Middle English from remain (v.). But the more usual noun in English has been remainder except in remains, euphemism for "corpse," attested from c. 1700, from mortal remains.
remain (v.): early 15c., from Anglo-French remayn-, Old French remain-, stressed stem of remanoir "stay, dwell, remain; be left; hold out," from Latin remanere "to remain, to stay behind; be left behind; endure, abide, last" (source also of Old Spanish remaner, Italian rimanere), from re- "back" (see re-) + manere "to stay, remain" (see mansion). Related: Remained; remaining.
remainder (n.): late 14c., from Anglo-French remainder, Old French remaindre, noun use of infinitive, a variant of Old French remanoir (see remain (v.)). The verb meaning "dispose of (books) at a reduced price" is from 1904. Related: Remaindered.
remake (v.): 1630s, from re- "back, again" + make (v.). Related: Remade; remaking. As a noun, of movies, from 1936.
remand (v.): mid-15c., from Middle French remander "send for again" (12c.) or directly from Late Latin remandare "to send back word, repeat a command," from Latin re- "back" (see re-) + mandare "to consign, order, commit to one's charge" (see mandate (n.)). Specifically in law, "send back (a prisoner) on refusing an application for discharge." Related: Remanded; remanding.
remanence (n.): 1660s, "that which remains," from remanent + -ence. Meaning "continuance, permanence" is from 1810.
remanent (adj.): "remaining," mid-15c., from Latin remanentem (nominative (see remanens), present participle of remanere (see remain (v.)).
remark (v.): 1630s, "to mark out, distinguish" modeled on French remarquer "to mark, note, heed," formed in Middle French from re-, intensive prefix (see re-), + marquer "to mark," probably from a Germanic source such as Old High German marchon "to delimit" (see mark (n.1)).

Meaning "take notice of" is from 1670s; that of "make a comment" is first attested 1690s, from notion of "make a verbal observation" or "call attention to specific points." Related: Remarked; remarking.
remark (n.): 1650s, "act of noticing; fact of being worthy of comment," from remark (v.). Meaning "a notice or comment" is from 1670s.
remarkable (adj.): c. 1600, from remark (v.) + -able, or from or based on French remarquable (16c.), from remarquer. "Observable, worthy of notice," hence "extraordinary, exceptional, conspicuous." Related: Remarkably.
remarriage (n.): 1610s, from re- + marriage.
remarry (v.): 1520s, from re- "back, again" + marry. Related: Remarried; remarrying.
rematch (n.): 1941, from re- "back, again" + match (n.) "contest."
rematch (v.): also re-match "to match again," 1856, from re- + match (v.). Related: Rematched; rematching.
rematerialize (v.): 1871, from re- + materialize. Related: Rematerialized; rematerializing.
remediable (adj.): 1560s, from Middle French remédiable, from Latin remediabilis "that may be healed, curable," from stem of remediare, from remedium (see remedy (n.)).
remedial (adj.): 1650s, "curing, relieving, affording a remedy," from Late Latin remedialis "healing, curing," from Latin remedium (see remedy (n.)). Educational sense of "concerned with improving skills" is first recorded 1924.
remediate (v.): 1969, back-formation from remediation. Related: Remediated; remediating.
remediation (n.): 1818, noun of action from stem of Latin remediare, from remedium "a cure, remedy" (see remedy (n.)). In educational jargon from c. 1975.
remedy (n.): c. 1200, "cure for a disease or disorder; means of counteracting an evil," from Anglo-French remedie, Old French remede "remedy, cure" (12c., Modern French remède) and directly from Latin remedium "a cure, remedy, medicine, antidote, that which restores health," from re-, intensive prefix (or perhaps literally, "again;" see re-), + mederi "to heal" (see medical (adj.)). Figurative use from c. 1300.
remedy (v.): c. 1400, from Old French remedier or directly from Latin remediare, from remedium (see remedy (n.)). Related: Remedied; remedying.
remember (v.): early 14c., "keep in mind, retain in the memory," from Old French remembrer "remember, recall, bring to mind" (11c.), from Latin rememorari "recall to mind, remember," from re- "again" (see re-) + memorari "be mindful of," from memor "mindful" (see memory). Meaning "recall to mind" is late 14c.; sense of "to mention" is from 1550s. Also in Middle English "to remind" (someone). An Anglo-Saxon verb for it was gemunan.
remembrance (n.): c. 1300, "a memory, recollection," from Old French remembrance (11c.), from remembrer (see remember). From late 14c. as "consideration, reflection; present consciousness of a past event; store of personal experiences available to recollection, capacity to recall the past." Also late 14c. as "memento, keepsake, souvenir," and "a commemoration, remembering, ritual of commemoration." Meaning "faculty of memory, capability of remembering" is early 15c.

British Remembrance Day, the Sunday nearest Nov. 11 (originally in memory of the dead of World War I) is attested from 1921. A remembrancer (early 15c.) was a royal official of the Exchequer tasked with recording and collecting debts due to the Crown; hence also, figuratively "Death" (late 15c.).
remilitarize (v.): 1920, originally of Soviet Russia, from re- + militarize. Related: remilitarized; remilitarizing.
remind (v.): 1640s, "to remember," from re- "again" + mind (v.). Meaning "to put (someone) in mind of (something)" is first recorded 1650s. Related: Reminded; reminding.
reminder (n.): "something which reminds," 1650s, agent noun from remind.
Remington (n.): type of firearms (1865) and typewriter (produced from 1874), from Eliphalet Remington (1793-1861) and his son Philo (1816-1889), gunsmiths of Ilion, N.Y.
reminisce (v.): 1829, "to recollect," back-formation from reminiscence. Meaning "indulge in reminiscences" is from 1871. "Somewhat colloquial" [OED]. Related: Reminisced; reminiscing.
reminiscence (n.): 1580s, "act of remembering," from Middle French reminiscence (14c.) and directly from Late Latin reminiscentia "remembrance, recollection" (a loan-translation of Greek anamnesis), from Latin reminiscentem (nominative reminiscens), present participle of reminisci "remember, recall to mind," from re- "again" (see re-) + minisci "to remember," from root of mens "mind," from PIE root *men- "mind, understanding, reason" (see mind (n.)). Meaning "a recollection of something past" is attested from 1811.
reminiscent (adj.): 1705, from Latin reminiscentem (nominative reminiscens), present participle of reminisci "call to mind, remember" (see reminiscence). Related: Reminiscential (1640s).
remise (v.): in law, "give up, surrender, make over to another," late 15c., from noun remise, from Old French remise, past participle of remettre "to send back," from Latin remittere (see remit). Related: Remised; remising.
remiss (adj.): early 15c., "weak, dissolved," from Latin remissus "relaxed, languid; negligent," past participle of remittere "slacken, abate, let go" (see remit). Meaning "characterized by lack of strictness" is attested from mid-15c.; that of "characterized by negligence" is from mid-15c.
remission (n.): c. 1200, "forgiveness or pardon (of sins)," from Old French remission "forgiveness (of sins), relief" (12c.), from Latin remissionem (nominative remissio) "relaxation, diminishing," lit. "a sending back, sending away," noun of action from past participle stem of remittere "slacken, let go, abate" (see remit). Used of diseases since early 15c.
remit (v.): late 14c., "to forgive, pardon," from Latin remittere "send back, slacken, let go back, abate," from re- "back" (see re-) + mittere "to send" (see mission). Meaning "allow to remain unpaid" is from mid-15c. Meaning "send money (to someone)" first recorded 1630s. Related: Remitted; remitting; remittent.
remittance (n.): 1705; see remit + -ance. Earlier in same sense were remitment (1610s of offenses; 1670s of money sent); remital (1590s).
remitter (n.): 1540s, a legal principle, from Old French remitter, noun use of infinitive, from Latin remittere "send back" (see remit). For legalese noun use of French infinitives, see waiver.
remnant (n.): late 14c., contraction of remenant (c. 1300), from Old French remanant "rest, remainder, surplus," noun use of present participle of remanoir "to remain" (see remain (v.)). Specific sense of "end of a piece of drapery, cloth, etc." is recorded from early 15c. An Old English word for "remnant" was endlaf.
remodel (v.): 1789, from re- "back, again" + model (v.). Related: Remodeled; remodeling.
remonstrance (n.): late 15c., from Middle French remonstrance (15c., Modern French remontrance), from Medieval Latin remonstrantia, from present participle stem of remonstrare "point out, show," from re-, intensive prefix (see re-), + Latin monstrare "to show" (see monster).
remonstrate (v.): 1590s, "make plain," back-formation from remonstration, or else from Medieval Latin remonstratus, past participle of remonstrare "to demonstrate" (see remonstrance). Meaning "to exhibit or present strong reasons against" is from 1690s. Related: Remonstrated; remonstrating.
remonstration (n.): late 15c., from Medieval Latin remonstrationem (nominative remonstratio), noun of action from past participle stem of remonstrare (see remonstrance).
remora (n.): 1560s, from Latin remora "sucking fish," literally "delay, hindrance," from re- "back" (see re-) + mora "delay" (see moratorium); so called because the fish were believed by the ancients to retard a vessel to which they attached themselves. Hence, in 17c.-18c., "an obstacle, an impediment" (the first sense of the word in Johnson's dictionary). In Greek, ekheneis, from ekhein "to hold" + naus (dative nei) "ship." Pliny writes that Antony's galley was delayed by one at Actium. Sometimes called in English stayship or stopship.
remorse (n.): late 14c., from Old French remors (Modern French remords), from Medieval Latin remorsum, noun use of neuter past participle of Latin remordere "to vex, disturb," literally "to bite back," from re- "back" (see re-) + mordere "to bite" (see mordant).

The sense evolution was via the Medieval Latin phrase remorsus conscientiæ (translated into Middle English as ayenbite of inwit). Middle English also had a verb, remord "to strike with remorse, touch with compassion, prick one's conscience."
remorseful (adj.): 1590s, from remorse + -ful. Related: Remorsefully; remorsefulness.
remorseless (adj.): 1590s, from remorse + -less. Related: Remorselessly; remorselessness.