castle (noun)
1: a large and stately mansion [syn: palace]
2: a large building formerly occupied by a ruler and fortified against attack
3: (chess) the piece that can move any number of unoccupied squares in a direction parallel to the sides of the chessboard [syn: rook]
4: interchanging the positions of the king and a rook [syn: castling] v : move the king two squares toward a rook and in the same move the rook to the square next past the king