An increasingly common unit of computer storage, comprising 1,024 megabytes or 1,073,741,824 bytes. Giga- is the prefix meaning "billion," so it is common to consider 1 gigabyte as equal to 1 billion bytes, although that isn't entirely accurate. It is not uncommon to find hard disks and magnetic cartridge media with storage capacities in excess of 1 gigabyte. Gigabyte is abbreviated GB, or, colloquially, "gig." 1,024 gigabytes equal 1 terabyte, which may yet become a common disk capacity.