mid-14c., "a bundle;" late 14c., "protuberance on the body, swelling, knob, lump," probably from Old French dialectal bonge "bundle," a nasalized form of Old French bouge (2), 15c., from Flemish bondje diminutive of boud "bundle." The sense of "a cluster, joined collection of things of the same kind" is from mid-15c. The looser meaning "a lot, a group of any kind" is from 1620s.
late 14c., "to bulge out," from bunch (n.). Meaning "to gather up in a bunch" (transitive) is from 1828; sense of "to crowd together" (intransitive) is from 1850. Related: Bunched; bunching.