noun: (uncountable) A chess opening characterized by the moves 1.e4 e5, in which both White and Black move their king's pawn to the fourth rank with their first move.
noun: (countable) Any of the set openings which begin in this way. (Ruy Lopez, Scotch Game, etc.)
noun: Alternative letter-case form of Open Game [(uncountable) A chess opening characterized by the moves 1.e4 e5, in which both White and Black move their king's pawn to the fourth rank with their first move.]
