Definition
A terminal air traffic control facility that provides airport traffic control service to aircraft operating in the vicinity of an airport, including the issuance of clearances and instructions for takeoff, landing, and movement on the runways and taxiways within its area of responsibility. A tower may also provide approach control services when combined with radar capability.
Plain English
The control facility at an airport, usually housed in the tall glass-topped building you can see from the ramp, that tells pilots when they can take off, land, and where they can move on the airport surface.
Context Anchor
Pilots encounter this term on airport radio calls, airport charts, and instructions at airports where controllers manage aircraft movement.
Derivation
Tower comes from an old word for a tall building or raised structure. That helps because airport control towers are built high so controllers can see the runways and nearby traffic, but in aviation the word usually means the control facility and its controllers, not just the building.
Why Pilots Care
At towered airports pilots must obtain clearances and instructions from the tower to take off, land, or taxi safely and to avoid conflicts with other aircraft.
Intuition Check
Tower does not just mean the tall building. In aviation use, it usually means the control facility and controllers who direct aircraft at and near the airport.
Example Sentence 1
After completing the run-up, the pilot called the tower and was cleared for takeoff on Runway 27.
Example Sentence 2
After landing, the tower directed the aircraft to turn left and taxi to parking.