past participle adjective from augment, c.1600. Musical sense is attested from 1825.
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- "to increase" (cf. 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.