Castle /(?)/

Cas·tle

Castle

n.
  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.
  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.

Phrases & Compounds
Castle in the air
a visionary project; a baseless scheme; an air castle; -- sometimes called a castle in Spain (F. Château en Espagne).

Castle

v. i.

imp. & p. p. Castled; p. pr. & vb. n. Castling

  1. To move the castle to the square next to king, and then the king around the castle to the square next beyond it, for the purpose of covering the king. (Chess)