Definition
An airport air traffic control facility, typically housed in a tall structure with a glass-walled cab on top, responsible for issuing clearances and instructions to aircraft operating on the runways and in the immediate airspace surrounding the airport. The tower controls takeoffs, landings, and movement on active runways, and at most towered airports it also coordinates traffic in the Class B, C, D, or E surface area airspace around the field.
Plain English
The control tower at an airport — the building where controllers watch the runways and surrounding sky and tell pilots when they can take off, land, or cross a runway.
Context Anchor
Seen in airport information, chart frequency boxes, radio procedures, and airport notices when identifying the tower or its radio frequency.
Derivation
From the physical structure itself — a tall tower built to give controllers a clear visual view of the entire airport surface and surrounding airspace. The abbreviation TWR is simply a shortened form used in printed publications and charts where space is tight.
Why Pilots Care
Contacting the correct TWR frequency provides the clearances needed for safe takeoff, landing, and taxi operations.
Intuition Check
Tower does not just mean the tall building. In aviation, it usually means the airport control facility or the controllers you communicate with.
Example Sentence 1
Cleared for takeoff by Tower, the pilot advanced the throttle and began the takeoff roll.
Example Sentence 2
TWR instructed the aircraft to hold short of the runway and monitor for landing traffic.