Source : Webster's Revised Unabridged Dictionary (1913)

Annulment \An*nul"ment\, n. [Cf. F. annulement.]
   The act of annulling; abolition; invalidation.

Source : WordNet®

annulment
     n 1: the state of being cancelled or annulled [syn: {revocation}]
     2: (law) a formal termination (of a relationship or a judicial
        proceeding etc) [syn: {invalidation}]
     3: the act of abrogating; an official or legal cancellation
        [syn: {abrogation}, {repeal}]