A file of multiple gigabytes in size, but it can also be used to describe any amount or quantity that's excessivly large.
"Did you see the size of that dude's email file? It was friggin' gigalicious."
"Man, that was a gigalicious amount of pizza you just ate."
"Man, that was a gigalicious amount of pizza you just ate."
by UkiMan September 14, 2006