| Noun | 1. | air passage - a duct that provides ventilation (as in mines)duct - an enclosed conduit for a fluid register - an air passage (usually in the floor or a wall of a room) for admitting or excluding heated air from the room schnorchel, schnorkel, snorkel breather, breather, snorkel - air passage provided by a retractable device containing intake and exhaust pipes; permits a submarine to stay submerged for extended periods of time upcast - air passage consisting of a ventilation shaft through which air leaves a mine ventilation shaft - a shaft in a building; serves as an air passage for ventilation |