an official announcement that something such as a law, agreement, or marriage no longer exists, or the process of making this announcement

Judges only grant marriage annulments in exceptional circumstances. 法官只在特殊情况下才宣布婚姻无效。

The discovery of the election fraud has led to the annulment of 50,000 votes. 选举舞弊的发现导致5万张选票被宣布为无效。