prominence n.

word-forming element meaning "forward, forth, toward the front" (as in proclaim, proceed); "beforehand, in advance" (prohibit, provide); "taking care of" (procure); "in place of, on behalf of" (proconsul, pronoun); from Latin pro (adv., prep.) "on behalf of, in place of, before, for, in exchange for, just as," which also was used as a first element in compounds and had a collateral form por-.

Also in some cases from cognate Greek pro "before, in front of, sooner," which also was used in Greek as a prefix (as in problem). Both the Latin and Greek words are from PIE *pro- (source also of Sanskrit pra- "before, forward, forth;" Gothic faura "before," Old English fore "before, for, on account of," fram "forward, from;" Old Irish roar "enough"), extended form of root *per- (1) "forward," hence "in front of, before, toward, near," etc.

The common modern sense of "in favor of, favoring" (pro-independence, pro-fluoridation, pro-Soviet, etc.) was not in classical Latin and is attested in English from early 19c.

Proto-Indo-European root meaning "to project." 

It forms all or part of: amenable; amount; cismontane; demeanor; dismount; eminence; eminent; imminence; imminent; menace; minacious; minatory; mons; montage; montagnard; monte; mount (n.1) "hill, mountain;" mount (v.) "to get up on;" mountain; mountebank; mouth; Osmond; Piedmont; promenade; prominence; prominent; promontory; remount; surmount; ultramontane.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit manya "nape of the neck;" Latin mons "mountain," eminere "to stand out;" Old Irish muin "neck," Welsh mwnwgl "neck," mwng "mane;" Welsh mynydd "mountain."