What's the origin of the word "GIG"?

Longtime audio guy Peter Stefan asked about the derivation of the word "gig". He was referring to the definition, "a job usu. for a specified time; esp.: an entertainer’s engagement. (This def courtesy of Merriam-Webster’s Collegiate® Dictionary).

The first historical reference for this meaning is documented as occuring in 1926, both in Webster’s and the OED. Both assert that the origin is unknown.

www.phoenix.net/~melanie/et_e-g.htm#carnival is an archive of "Your Etymology Questions", wherein it is suggested, "…gig-a musical performance, likely comes from French gigue ‘a ball or dance’, from Middle French giguer ‘to dance’. Jig (the verb) likely comes from the same source."

Now, no dictionary I checked (six or so) gives the word gig this definition, let alone this derivation, so I place little credence in this source.

Gig is truly a hard-working word. The earliest meaning of gig is Sumerian, in which it means black or dark. If you go back just a few hundred years, it refers to the vagina AND the asshole. Later in history, definitions include: something that whirls or is whirled; a 3-digit selection in a numbers game; a person of odd or grotesque appearance; a long light ship; a rowboat designed for speed rather than for work; a light two-wheeled one-horse carriage; a pronged spear for catching fish; a military demerit…and that’s just the nouns!

The etymology for this slew of meanings varies, but the specific meaning about which Peter queried seems to have no identified derivation. Sorry Pete, I guess I blew this gig. No, not THAT kind of gig! What a mind!