(1):

(n.) A cowl-shaped cap, commonly turning with the wind, used to improve the draft of a chimney, ventilating shaft, etc.

(2):

(n.) A wire cap for the smokestack of a locomotive.

(3):

(n.) A vessel carried on a pole between two persons, for conveyance of water.

(4):

(n.) A monk's hood; - usually attached to the gown. The name was also applied to the hood and garment together.