What is Rook?

A Rook is a piece in the game of chess. Each player starts the game with two rooks. Resembling a castle turret, it is usually represented on the chessboard. The Rook can move any number of squares along its rank or file (horizontally or vertically) but cannot leap over other pieces. Along with the king, the rook is also involved during the king's castling move.

See Moving the rook.