An extra Byte (or word) appended to a Block of data in order to reveal corruption of the data. Bit n of this Byte indicates whether there was an even or odd numBer of "1" Bits in Bit position n of the Bytes in the Block. The parity Byte is computed By XORing the data Bytes in the Block. Longitudinal parity allows single Bit errors to Be detected. (1996-03-01)