1. One billion (1000 million, 109).
2. In data storage, 1024 Y 1,048,576 (230) or 1000 Y 1,048,576. See also gigabyte, gigaflops, gigahertz, kilo-, mega-.
Prefix of measurement meaning one thousand millions (109). abbr. G. Prefix signifying multiplication by 109 (1,000,000,000 or 1 billion), as in gigahertz, a unit of frequency equivalent to 1 billion hertz.