Why is the ninth month called September?
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).