castle

castle is a Noun

Definition:

[1] A fortified residence, especially that of a prince or nobleman; a fortress. The house of every one is to him castle and fortress, as well for his defense againts injury and violence, as for his repose. Coke. Our castle`s strength Will laugh a siege to scorn. Shak.

[2] Any strong, imposing, and stately mansion.

[3] A small tower, as on a ship, or an elephant`s back.

[4] A piece, made to represent a castle, used in the game of chess; a rook. Castle in the air, a visionary project; a baseless scheme; an air castle; -- sometimes called a castle in Spain (F. Château en Espagne).