A more thorough explanation:

Definition: A canceled check is a check that has been paid by the bank on which it was drawn and bears a notation to that effect. It is often used as evidence of payment.

Example: John writes a check to his landlord for rent. The landlord deposits the check in his bank account, and the bank processes the check and pays the landlord. The bank then marks the check as "canceled" and returns it to John as proof of payment.

This example illustrates how a canceled check serves as evidence that a payment has been made. Once the bank has paid the check, it is canceled and cannot be used again. The canceled check provides a record of the payment and can be used to prove that a debt has been satisfied.