(1):
(n.) A room in a tower in which a bell is or may be hung; or a cupola or turret for the same purpose.
(2):
(n.) A bell tower, usually attached to a church or other building, but sometimes separate; a campanile.
(3):
(n.) The framing on which a bell is suspended.
(4):
(n.) A movable tower erected by besiegers for purposes of attack and defense.