Definition of en passant rule (or law) in English:

en passant rule (or law)

phrase

Chess
  • The rule that a pawn making a first move of two squares instead of one may nevertheless be immediately captured by an opposing pawn on the fifth rank.

    • ‘This en passant rule must happen on the current move of the game.’
    • ‘Although you may play a hundred games, and never have to use the En Passant rule, you should know it if your opponent uses it.’