'Strikeout' definitions:

Definition of 'strikeout'

From: WordNet
noun
An out resulting from the batter getting three strikes

Definition of 'Strikeout'

From: GCIDE
  • Strikeout \Strike"out\, n. (Baseball) an out made by a batter against whom three strikes were called in a single at-bat; also, the same out as credited to the pitcher, in the scoring of the game. [PJC]