Short for gigabyte, which is one billion bytes as determined by the prefix 'gig,' meaning one billion, in front of 'byte.' To be more thorough, the quantifier 'gig' can specify different exact values depending upon context. For example, when working with things that typically come in standard units of 10 like money or distances it is accepted as meaning 1000 to the power of 3 (one billion). However, when working in things that tend to come in multiples of 2 like computer bytes it is thought of as 2 to the power of 30 (or 1024 to the power of 3), which is precisely 1,073,741,824 - a little over a billion, but who's counting?

Gig also refers to a performance by a musician or group of musicians, especially in modern or pop music.