recollection (n.)

word-forming element meaning "back, back from, back to the original place;" also "again, anew, once more," also conveying the notion of "undoing" or "backward," etc. (see sense evolution below), c. 1200, from Old French re- and directly from Latin re- an inseparable prefix meaning "again; back; anew, against."

Watkins (2000) describes this as a "Latin combining form conceivably from Indo-European *wret-, metathetical variant of *wert- "to turn." De Vaan says the "only acceptable etymology" for it is a 2004 explanation which reconstructs a root in PIE *ure "back."

In earliest Latin the prefix became red- before vowels and h-, a form preserved in redact, redeem, redolent, redundant, redintegrate, and, in disguise, render (v.). In some English words from French and Italian re- appears as ra- and the  following consonant is often doubled (see rally (v.1)).

The many meanings in the notion of "back" give re- its broad sense-range: "a turning back; opposition; restoration to a former state; "transition to an opposite state." From the extended senses in "again," re- becomes "repetition of an action," and in this sense it is extremely common as a formative element in English, applicable to any verb. OED writes that it is "impossible to attempt a complete record of all the forms resulting from its use," and adds that "The number of these is practically infinite ...."   

Often merely intensive, and in many of the older borrowings from French and Latin the precise sense of re- is forgotten, lost in secondary senses, or weakened beyond recognition, so that it has no apparent semantic content (receive, recommend, recover, reduce, recreate, refer, religion, remain, request, require). There seem to have been more such words in Middle English than after, e.g. recomfort (v.) "to comfort, console; encourage;" recourse (n.) "a process, way, course." Recover in Middle English also could mean "obtain, win" (happiness, a kingdom, etc.) with no notion of getting something back, also "gain the upper hand, overcome; arrive at;" also consider the legal sense of recovery as "obtain (property) by judgment or legal proceedings." 

And, due to sound changes and accent shifts, re- sometimes entirely loses its identity as a prefix (rebel, relic, remnant, restive, rest (n.2) "remainder," rally (v.1) "bring together"). In a few words it is reduced to r-, as in ransom (a doublet of redemption), rampart, etc.

It was used from Middle English in forming words from Germanic as well as Latin elements (rebuild, refill, reset, rewrite), and was used so even in Old French (regret, regard, reward, etc.).

Prefixed to a word beginning with e, re- is separated by a hyphen, as re-establish, re-estate, re-edify, etc. ; or else the second e has a dieresis over it: as, reëstablish, reëmbark, etc. The hyphen is also sometimes used to bring out emphatically the sense of repetition or iteration : as, sung and re-sung. The dieresis is not used over other vowels than e when re is prefixed : thus, reinforce, reunite, reabolish. [Century Dictionary, 1895]

early 15c., "gather into one place or group" (transitive), from Old French collecter "to collect" (late 14c.), from Latin collectus, past participle of colligere "gather together," from assimilated form of com "together" (see com-) + legere "to gather," from PIE root *leg- (1) "to collect, gather."

The intransitive sense "gather together, accumulate" is attested from 1794. Related: Collected; collecting. As an adjective or adverb meaning "paid by the recipient," it is attested from 1893, originally with reference to telegrams.

"to recover or recall knowledge of, bring back to the mind or memory," 1550s, from Latin recollectus, past participle of recolligere "to take up again, regain," etymologically "to collect again," from re- "again" (see re-) + colligere "gather" (see collect (v.)). Related: Recollected; recollecting. In form and origin identical with re-collect, but the pronunciation and sense depend upon the noun recollection.

Remember implies that a thing exists in the memory, not that it is actually present in the thoughts at the moment, but that it recurs without effort. Recollect means that a fact, forgotten or partially lost to memory, is after some effort recalled and present to the mind. Remembrance is the store-house, recollection the act of culling out this article and that from the repository. He remembers everything he hears, and can recollect any statement when called on. The words, however, are often confounded, and we say we cannot remember a thing when we mean we cannot recollect it. [Century Dictionary, 1895]