a fortified, protected building, usually with a wall around it, owned by a prince or noble esp. in former times.
a large and stately residence, esp. one that imitates the forms of a medieval castle.
any place providing security and privacy:the old saying, a man's home is his castle.
ChessChess. the rook; one of the two corner pieces in the first row.
ChessChess. to move (the king) two squares to the side and bring the rook to the square the king has passed over: [~ + object]He castled his king as a final defense.[no object]He tried castling to protect his king.
to move (the king) two squares laterally on the first rank and place the nearest rook on the square passed over by the king, either towards the king's side (castling short) or the queen's side (castling long)
Etymology: 11th Century: from Latin castellum, diminutive of castrum fort