castle vs great hall

castle and great hall both are nouns.

Word	Noun	Adjective	Verb	Adverb
castle	Yes	No	Yes	No
great hall	Yes	No	No	No

castle (noun)	great hall (noun)
interchanging the positions of the king and a rook	the principal hall in a castle or mansion; can be used for dining or entertainment
a large building formerly occupied by a ruler and fortified against attack
(chess) the piece that can move any number of unoccupied squares in a direction parallel to the sides of the chessboard
a large and stately mansion

castle (verb)	great hall (verb)
move the king two squares toward a rook and in the same move the rook to the square next past the king