(1):

(n.) An upper servant of an inn.

(2):

(n.) An officer having the direction and management of the private chambers of a nobleman or monarch; hence, in Europe, one of the high officers of a court.

(3):

(n.) An officer or servant who has charge of a chamber or chambers.

(4):

(n.) A treasurer or receiver of public money; as, the chamberlain of London, of North Wales, etc.