Definition
An authorization issued by ATC for an aircraft to move on the airport surface along a specified route, typically to or from a runway. The clearance includes the route to follow and any hold-short instructions, and must be read back by the pilot before taxiing begins.
Plain English
Permission from the control tower to move your aircraft on the ground, along the route they tell you, until they say to stop or until you reach where you're going.
Context Anchor
Heard at towered airports when a pilot asks ground control or tower for permission to move from parking, the ramp, or another ground location toward a runway or parking area.
Derivation
‘Taxi’ in aviation comes from early pilots describing the slow ground movement of aircraft as similar to a taxicab moving through streets. ‘Clearance’ means formal permission. Together: formal permission to move along the ground.
Why Pilots Care
Coordinates ground movement to prevent conflicts with other aircraft, vehicles, or runways.
Intuition Check
Do not read clearance as “the path is clear, so I can go anywhere.” A taxi clearance is specific permission to move only as ATC instructed, and it is not a takeoff clearance.
Example Sentence 1
After engine start, the pilot called Ground and received a taxi clearance to Runway 27 via taxiways Alpha and Bravo.
Example Sentence 2
After clearing the runway, the controller issued a taxi clearance back to the ramp.