Annulment is the official act — or the paper result — of wiping out a marriage or a legal agreement, so that in law it no longer exists, and often is treated as if it never did. If a court grants an annulment, it is not merely ending the marriage; it is saying the marriage was not valid. People also speak of the annulment of a contract or a decision. It is a law-and-church noun. You will not hear it about everyday cancellations (a cancelled trip is not an annulment).