(1):

(n.) A short tube, usually tapering, forming the vent of a hose or pipe.

(2):

(n.) A short outlet, or inlet, pipe projecting from the end or side of a hollow vessel, as a steam-engine cylinder or a steam boiler.

(3):

(n.) The nose; the snout; hence, the projecting vent of anything; as, the nozzle of a bellows.