c.1400, from Old French augmenter "increase, enhance" (14c.), from Late Latin augmentare "to increase," from Latin augmentum "an increase," from augere "to increase, make big, enlarge, enrich," from PIE root *aug- (1) "to increase" (cognates: Sanskrit ojas- "strength;" Lithuanian augu "to grow," aukstas "high, of superior rank;" Greek auxo "increase," auxein "to increase;" Gothic aukan "to grow, increase;" Old English eacien "to increase"). Related: Augmented; augmenting. As a noun from early 15c.