- a fortified, usually walled residence, as of a prince or noble in feudal times.
- the chief and strongest part of the fortifications of a medieval city.
- a strongly fortified, permanently garrisoned stronghold.
- a large and stately residence, especially one, with high walls and towers, that imitates the form of a medieval castle.
- any place providing security and privacy: It may be small, but my home is my castle.
- Chess. the rook.
verb (used with object), cas·tled, cas·tling.
- to place or enclose in or as in a castle.
- Chess. to move (the king) in castling.
verb (used without object), cas·tled, cas·tling. Chess.
- to move the king two squares horizontally and bring the appropriate rook to the square the king has passed over.
- (of the king) to be moved in this manner.
- a fortified building or set of buildings, usually permanently garrisoned, as in medieval Europe
- any fortified place or structure
- a large magnificent house, esp when the present or former home of a nobleman or prince
- the citadel and strongest part of the fortifications of a medieval town
- chess another name for rook 2
- chess 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)
move in chess, recorded under this name from 1650s, from castle (n.), as an old alternative name for the rook, one of the pieces moved. Related: Castled; castling.
late Old English castel “village” (this sense from a biblical usage in Vulgar Latin); later “large fortified building, stronghold,” in this sense from Old North French castel (Old French chastel, 12c.; Modern French château), from Latin castellum “a castle, fort, citadel, stronghold; fortified village,” diminutive of castrum “fort,” from Proto-Italic *kastro- “part, share;” cognate with Old Irish cather, Welsh caer “town” (and perhaps related to castrare via notion of “cut off;” see caste). In early bibles, castle was used to translate Greek kome “village.”
This word also had come to Old English as ceaster and formed the -caster and -chester in place names. Spanish alcazar “castle” is from Arabic al-qasr, from Latin castrum. Castles in Spain translates 14c. French chastel en Espaigne (the imaginary castles sometimes stood in Brie, Asia, or Albania) and probably reflects the hopes of landless knights to establish themselves abroad. The statement that an (English) man’s home is his castle is from 16c.