checker

Checker is a term with multiple related meanings. It can refer to a small playing piece used in the board game checkers (draughts), to a person or device that checks or verifies something, or to the act of checking itself. The term is also associated with checkered patterns, describing surfaces divided into alternating squares.

In the game checkers, each player uses several checkers, typically discs of a single color, placed on the dark squares of the board. Checkers move one diagonal square at a time and capture by leaping over an adjacent opposing piece. When a piece reaches the farthest row, it is crowned a king, gaining the ability to move and capture both forward and backward.

In computing and data processing, a checker is a component that validates a condition or result. This can include input validation, data integrity checks such as checksums, or output checkers used in automatic judging systems. In programming contests, a checker compares a participant's output against the problem's requirements and can allow for specified tolerances or formatting differences.

Beyond games and software, checker can refer to a person who inspects goods in quality control or compliance roles. The term also appears in contexts such as fabrics or design patterns described as checkered, and in various brand or corporate names.