A bit can either be on or off; one or zero. All computer data can ultimately be reduced to a series of bits. The term is also used as a (very rough) measure of sound quality, color quality, and even procesor capability by considering the fact that series of bits can represent binary numbers. For example (without getting too technical), an eight bit image can contain at most 256 distinct colors while a sixteen bit image can contain at most 65,536 distinct colors.