cancellation

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or an instance of canceling.
• noun A mark or a perforation indicating canceling.
• noun Something canceled, especially a released accommodation or an unfilled appointment.

from The Century Dictionary.

• noun In gastropods, the system of intersecting ridges on the surface of the shell.
• noun See cancelation.
• noun In anatomy, reticulation; the state of being cancellated: as, the cancellation of bone.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act, process, or result of canceling.
• noun (Math.) The operation of striking out common factors, in both the dividend and divisor.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

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

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the act of cancelling; calling off some arrangement
• noun the speech act of revoking or annulling or making void