Just checked the etymology site World Wide Words. It confirms the obscure origin of the word, repeating much of what has been said here. I've copied their article:


The term is usually taken to be of American origin, but the interesting thing is that the first two citations in the Oxford English Dictionary are from a London publication, Melody Maker, in 1926 and 1927. So the word in this sense has long been known in Britain.

Gig is yet another of those words for which researchers can give no firm origin, and what follows is largely supposition, following the leads given by Dr Jonathan Lighter in the Random House Historical Dictionary of American Slang.

The oldest sense of gig was of something that whirled or turned (as in whirligig); much later it was applied to a fast two-wheeled carriage, presumably because its big wheels went around quickly, and later to a fast ship's boat. There are many other senses.

From the 1840s in the US, Mr Lighter shows it also applied to a form of betting, involving a set of three or five numbers selected by the bettor. From his examples, it seems the winning numbers were drawn from a rotating device, called a wheel, presumably like a lottery or tombola drum, which must be the link to the name. By the beginning of the twentieth century, Mr Lighter suggests the word had begun to be applied more generally to a business, state of affairs, or an undertaking or event. This may have been influenced by a similar sense of gag that had come into being by the 1890s.

However, the great majority of Mr Lighter's examples in this sense date from 1957 or later, with only one from 1907 to suggest that it pre-dated the application of gig to an engagement to perform live music. This is why dictionaries are cautious about accepting this sequence of development of the word, even though it seems to be plausible.

These days, gig can have a wide range of senses, including a fairly new one that refers to any short-term paying commission or job; it need not be associated with music or performance, but it does preclude permanent full-time employment.


By the way, I heard one of my kids use "gig" the other night to mean a rock (or whatever they call it now) music show, as in "We're going to a gig later tonight" (i.e., as spectators). It seems to have acquired that additional meaning among his crowd at least.