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early 14c., "protuberance on the body, swelling," perhaps echoic of the sound of hitting and connected to bump (cf., possibly in similar relationship, hump/hunch).
The sense of "cluster" is mid-15c.; connection with the earlier sense is obscure, and this may be a separate word, perhaps through a nasalized form of Old French bouge (2), 15c., from Flemish boudje diminutive of boud "bundle." Meaning "a lot, a group" is from 1620s.
"to bulge out," late 14c., from bunch (n.). Meaning "to gather up in a bunch" (transitive) is from 1828; sense of "to crowd together" (intransitive) is from 1873. Related: Bunched; bunching.
(1.) A bundle of twigs (Ex. 12:22). (2.) Bunch or cake of raisins (2 Sam. 16:1). (3.) The "bunch of a camel" (Isa. 30:6).