Definition:Chess/Rules/Checkmate

Definition
If player $a$ has put player $b$'s king in check, but player $b$ has no legal move that will get him or her out of check, then player $a$ has won.

This situation is known as checkmate.

player $a$ is said to have checkmated player $b$.

Also known as
The abbreviated mate is often heard, particularly in the triumphant announcement by the winning player, as he spanks down his piece:
 * "Check and mate."