The fundamental data unit of personal computers, a byte is eight contiguous bits. The byte is also the basic unit of measurement for computer storage, storing the equivalent of one character. Computer architecture is based mostly on binary numbers, so bytes are counted in powers of two (which is why some people prefer to call groups of eight bits "octets"). The terms kilo (in kilobyte, abbreviated as K) and mega (in megabyte, abbreviated as M) are used to count bytes (even though they are misleading, since they derive from a decimal base of 10 numbers).
NetLingo Classification: Technical Terms