What is Chamberlain?

Legal Definition
Keeper of the chamber. Originally the chamberlain was the keeper of the trcasure chamber (camera) of the prince or state; otherwise called "treasurer." Cowell. The name of several high officers of state in England, as the lord great chamberlain of England, lord chamberlain of the household, chamberlain of the exchequer. Cowell; Blount. The word is also used in some American cities as the title of an officer corresponding to "frcasurer."
-- Black's Law Dictionary
Legal Definition
-- Ballentine's Law Dictionary