A fixed number of bits that can be treated as a unit by the computer hardware. It is a subdivision of a word, and almost always comprises 8 bits although 6, 7, or 9 bits are occasionally encountered.

The letters B and b are commonly used as symbols for byte, as in MB (megabyte), and GB (gigabyte), although the word is often written in full in such cases, as in Mbyte.

See also character.