the world > action or operation > safety > protection or defence > care, protection, or charge > [noun] > one who looks after > guardian or custodian > custodian of building > of a castle (4)
The governor or warden of a royal fortress or castle. (Still the official title of the governors of some royal castles in England.)
The governor or constable of a castle.
The governor or keeper of a castle; = castellan, n.
= chastelain, n., castellan, n. (Obsolete as an English title.)