bit field <data> Part of an item of data, storage location or message, identified as a certain number of contiguous {bits} starting at a certain bit position within the data. Bit position zero is usually the least significant bit. For example, in an {ARM} {machine code} instruction the four-bit field at bits 28 to 31 (the four most significant bits in the 32-bit word) is the "condition code". (2007-03-26)