(n.) The vent of a cannot or other firearm, by which fire is communicateed to the powder of the charge.

CAT aerospace aerosphere air duct air passage air pocket air shaft air tube airspace airway armhole blowhole breathing hole bullet-hole bump bunghole ceiling cringle crosswind deadeye empty space eye eyelet favorable wind fog front gasket grommet guide head wind high-pressure area hole ionosphere jetstream keyhole knothole loop loophole louver louverwork low-pressure area manhole mousehole naris nostril overcast peephole pigeonhole pinhole placket placket hole pocket porthole punch-hole roughness shaft soup space spilehole spiracle stratosphere substratosphere tail wind tap touchhole transom tropopause troposphere trough turbulence vent ventage venthole ventiduct ventilating shaft ventilator visibility visibility zero wind tunnel