Plain English Meaning
A small gauge in the cockpit that tells the pilot how hot or cold the air is outside the aircraft.
Full Definition
A cockpit instrument that displays the temperature of the ambient air outside the aircraft, typically measured by a probe mounted on the airframe where it is exposed to the free airstream. The reading is used by the pilot to assess conditions affecting engine performance, density altitude, carburetor icing risk, and true airspeed calculations.
Context Anchor
Seen on the instrument panel and in discussions of carburetor ice and - risk.