re-mark v.

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]

"to put a mark on," Old English mearcian (West Saxon), merciga (Anglian) "to trace out boundaries;" in late Old English "make a mark or marks on," from Proto-Germanic *markojan (source also of Old Norse merkja, Old Saxon markon "appoint, observe, remark," Old Frisian merkia, Old High German marchon "to limit, plan out," German merken "to mark, note," Middle Dutch and Dutch merken "to set a mark on"), from the root of mark (n.1).

Influenced by the Scandinavian cognates. Meaning "to have a mark" is from c. 1400; that of "to notice, observe" is late 14c. Figurative sense of "designate as if by placing a mark on," hence "to destine," is from late Old English. Meaning "be a noteworthy feature of" is by 1660s. To mark time (1833) is from military drill, originally "move the feet as if marching but remain in place."

The verbs in Romanic are from the nouns, which are early borrowings from Germanic: Old French merchier "to mark, note, stamp, brand," French marquer "to mark," Spanish marcar, Italian marcare.

1630s, "to mark out, distinguish," a sense now obsolete, modeled on French remarquer "to mark, note, heed," formed in French from re-, here perhaps an intensive prefix (see re-), + marquer "to mark," which probably is from Frankish or another Germanic source such as Old High German marchon "to delimit" (see mark (n.1)).

Meaning "take notice of, mark out in the mind" is from 1670s; that of "make a comment, express, as a thought that has occurred to the speaker or writer" is attested from 1690s, from the notion of "make a verbal observation" or "call attention to specific points." Related: Remarked; remarking.