An opening in a building’s envelope whose purpose is to allow outside air to be drawn in to replace inside air.
An intake or (for aircraft) inlet is an opening on a car or aircraft body capturing air for operation of an internal combustion engine.
Because the modern ground vehicle internal combustion engine is in essence a powerful air pump, like the exhaust system on an engine, the intake must be carefully engineered and tuned to provide the greatest efficiency and power. An ideal intake system should increase the velocity of the air until it travels into the combustion chamber, while minimizing turbulence and restriction of flow.
However, in aircraft, particularly supersonic aircraft, the purpose of the intake is to slow and increase the pressure of the air.