An error detection method in which that total number of ones in a binary work, byte, character, or message is set to an odd or even number by appending a redundancy bit. This number is subsequently checked to ensure that it remains odd or even; typically used as an error detection technique in communication and data storage.

A code that is used to uncover data error by making the sum of the "1" bits in a data unit either an odd or even number.

The concept of parity is a check on the accuracy of data. "Even parity" is defined to mean that the number of binary 1's in a digital work is an even number, "odd parity" means that the number of 1's is an odd number. Memory boards, for example, have circuitry that maintains either one parity or the other during a write; if that same parity is not present when the data is read, an error is signaled.