montage n.

c. 1300, mounten, "to get up on a horse;" mid-14c., "to rise up, rise in amount, ascend; fly," from Old French monter "to go up, ascend, climb, mount," from Vulgar Latin *montare, from Latin mons (genitive montis) "mountain" (from PIE root *men- (2) "to project"). The transitive meaning "to set or place in position" first recorded 1530s. Sense of "to get up on for purposes of copulation" is from 1590s. Meaning "prepare for presentation or exhibition" is by 1712. Military meaning "set up or post for defense" is by 1706; to mount an attack is by 1943. Related: Mounted; mounting.

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." 

"use of photographs or photographic negatives to make art or illustration," 1931, from photo + montage.