1. a combining form meaning “billion,” used in the formation of compound words: gigabyte.

Origin of giga-

From the Greek word gígāsgiant

Words Nearby giga- Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use giga- in a sentence

  • Each number received minute attention, the Giga being played by Ethelbert Nevin.

    Piano Mastery | Harriette Brower
  • The name comes from Giga (Geige), a sort of fiddle in use during the 12th and 13th centuries.

    Shakespeare and Music | Edward W. Naylor

British Dictionary definitions for giga-


/ (ˈɡɪɡə, ˈɡaɪɡə) /

combining form
  1. denoting 10 9: gigavolt Symbol: G

  2. (in computer technology) denoting 2 30: gigabyte

Origin of giga-

from Greek gigas giant

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for giga-


  1. A prefix that means:

  2. One billion (109), as in gigahertz, one billion hertz.

  1. 230 (that is, 1,073,741,824), which is the power of 2 closest to a billion, as in gigabyte.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.