n.[C]

1. 城堡
   The baron lived in a strong castle.

   男爵住在一座堅固的城堡中。

2. 城堡式建築，巨宅
3. （西洋棋的）城形棋子

vt.

1. 置……於城堡中；築城堡防禦

n.

1. a large building, typically of the medieval period, which is (or was formerly) fortified as a stronghold.
2. Chess,  informal old-fashioned term for rook².

v.

Chess  move one's king from its original square two squares along the back rank towards a rook on its corner square which is simultaneously moved to the square passed over by the king.