Noun

1. The act, process, or result of canceling; as, the cancellation of certain words in a contract, or of the contract itself.
2. The operation of striking out common factors, in both the dividend and divisor.
3. A postmark that marks a postage stamp so as to prevent its reuse.
4. In United States intellectual property law, a proceeding in which an interested party seeks to cancel the registration of a trademark or patent.