an enclosed conduit for a fluid

a hole for the escape of gas or air

an air passage (usually in the floor or a wall of a room) for admitting or excluding heated air from the room

air passage provided by a retractable device containing intake and exhaust pipes; permits a submarine to stay submerged for extended periods of time

air passage consisting of a ventilation shaft through which air leaves a mine

a shaft in a building; serves as an air passage for ventilation

a hole for the escape of gas or air