Noun:

1. the state of being cancelled or annulled

2. the act (by someone having the authority) of annulling something previously done;

   "the revocation of a law"
   

annulmentn.废除；取消；宣告婚姻无效

cancellationn.取消；撤销；废除

withdrawaln.撤退；退回；取消

reversaln.翻转；倒转；反转

overturningn.倒转；推翻动词overturn的现在分词.

1. No proceedings for the forfeiture or revocation of a patent may be instituted before the expiration of two years from the grant of the first compulsory license.
   自授予第一个强制许可之日起两年届满前不得提起取消或撤消专利的诉讼。