Definition
A descriptor used in instrument approach procedures at an airport without an operating control tower, indicating that an Approach Control facility provides radar or non-radar separation, sequencing, and approach clearances to arriving IFR aircraft until they are handed off or proceed inbound on the approach. Aircraft operating to such an airport remain in two-way radio contact with Approach Control rather than a tower, and switch to the Common Traffic Advisory Frequency (CTAF) only after being released or cancelling IFR.
Plain English
The airport has no tower of its own, but a nearby radar facility (Approach Control) talks you down, spaces you with other traffic, and clears you for the approach. You stay with that controller until they release you, then switch to the local advisory frequency to announce yourself to other pilots in the pattern.
Context Anchor
Seen when planning or flying an instrument approach to an airport without an operating control tower.
Derivation
Approach means coming near or arriving. Control means directing or managing. In this phrase, Approach Control is the ATC service that manages aircraft as they get close to an airport, not a tower located at that airport.
Why Pilots Care
Allows safe sequencing into a busy non-towered airport without creating conflicts in the traffic pattern.
Intuition Check
With an Approach Control does not mean the destination airport has an operating tower. It means approach-control service is available for the area while the airport itself may still be non-towered.
Example Sentence 1
Because the destination is a non-towered field with an Approach Control, we'll get our approach clearance from the radar controller and switch to CTAF once we're released.
Example Sentence 2
Even without a tower, pilots at this field are expected to follow approach control instructions until established on the visual approach.