Synonyms for castle

noun

• a large and stately mansion
• (chess) the piece that can move any number of unoccupied squares in a direction parallel to the sides of the chessboard
• interchanging the positions of the king and a rook
• a large building formerly occupied by a ruler and fortified against attack

verb

• move the king two squares toward a rook and in the same move the rook to the square next past the king