exhaust port; exhaust vent; exhaust outlet
An opening through which exhaust gas or air is discharged, commonly found on vehicles, machinery, or ventilation systems.
White smoke is coming out of the car's exhaust port.
The exhaust vent in this room needs regular cleaning.
吸気口 is an intake port, the opposite of 排気口.
Compound of 排気 (exhaust) + 口 (opening, mouth).