(Or "IEC prefix") A prefix used with a unit of data to mean multiplication by a power of 1024. Binary prefixes are most often used with "byte" (e.g. "kilobyte") but also with bit (e.g. "megabit"). For example, the term kilobyte has historically been used to mean 1024 bytes, and megabyte to mean 1,048,576 bytes. The multipliers 1024 and 1,048,576 are powers of 1024, which is itself a power of two (1024 = 2^10). It is this factor of two that gives the name "binary prefix".