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.

    ‘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.’
    ‘This en passant rule must happen on the current move of the game.’