Glossary of Chess

Waiting move: A passive but harmless move, which is played while waiting for initiative from the opponent.
Weak square: A square that cannot be easily defended from attack by an opponent. Often a weak square is unable to be defended by pawns (a hole) and can be theoretically occupied by a piece. Exchange or loss of a bishop may make all squares of that bishop's color weak resulting in a "weak square complex" on the light squares or the dark squares.
WFM: Abbreviation for the Woman FIDE Master title.
WGM: Abbreviation for the Woman Grandmaster title.
White (See White and Black in chess): The designation for the player who moves first, even though the corresponding pieces, referred to as "the white pieces", are sometimes actually some other (usually light) color. Similarly, the light-colored squares on the chessboard are often referred to as "the white squares" even though they often are not literally white. See also Black, First-move advantage in chess.
Wild: An extremely unclear or mind–bogglingly complicated position or move.
WIM: Abbreviation for the Woman International Master title.
Win: A victory for one of the two players in a game, which may occur due to checkmate, resignation by the other player, the other player exceeding the time control, or the other player being forfeited by the tournament director. Chess being a zero-sum game, this results in a loss for the other player.
Win/winning position: A position is said to be a win (or a winning position) if one specified side, with correct play, can eventually force a checkmate against any defence (i.e. perfect defence).
Windmill: A combination in which two pieces work together to deliver an alternating series of checks and discovered checks in such a way that the opposing king is required to move on each turn. It is a potent technique since on every other move, the discovered check may allow the non-checking piece to capture an enemy piece without losing a tempo. The most famous example is Torre–Lasker, Moscow 1925. Also called a see-saw.
Wing: The queenside a, b, and c-files, or the kingside f, g, and h-files, also called flank.
Wing Gambit: Is the name given to variations of several openings in which one player gambits a wing pawn, usually the b pawn.
Winning percentage: A number calculated by taking the percentage of games won by a player plus half the percentage of drawn games. Thus, if out of 100 games a player wins 40, draws 32, and loses 28, her winning percentage is 40 plus half of 32, i.e. 56 percent.
Woman FIDE Master (WFM): A women-only chess title ranking below Woman International Master.
Woman Grandmaster (WGM): The highest ranking gender-restricted chess title except for Women's World Champion.
Woman International Master (WIM): A women-only chess title ranking below Woman Grandmaster and above Woman FIDE Master.
Woodpusher: A weak chess player, also referred to as a "fish", "patzer" or "duffer".
World Champion: A winner of the World Chess Championship.
Wrong bishop: See Wrong rook pawn.
Wrong rook pawn: With a bishop, a rook pawn may be the wrong rook pawn, depending on whether or not the bishop controls its promotion square.