from gigue. A short piece of music much in vogue in olden times, of a very lively character, either six-eight or twelve-eight time, and used for dance-tunes. It consists of two parts, each of eight bars. Also a comic song.
“You jig, you amble, and you lisp.” —
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Jig from Infoplease: