A prefix appended to a unit to indicate some multiple of that unit, usually multiples of 1,000. For example:
In computing, metric prefixes are used to indicate multiple quantities of bits and bytes. For example, one kilobit is equal to approximately 1,000 bits. (Actually, since computing is based on a binary system, not a decimal one, "kilo-" is used to refer to 210, which equals 1,024, the closest number to 1,000). See Kilo-, Mega-, Giga-, Tera-, Peta-, and Exa-.