Glossary - G
Gigabyte (GB) - one thousand million (1,000,000,000) bytes - strictly 230 = 1,073,741,824 bytes. See also Byte.
Greyscale - a colour space that uses a single element of 8 bits to create 255 shades of grey between, and including, black and white. Whereas the RGB colour space uses three elements of 8 bits each.