Plain English Meaning

The controller who tells you where and how to taxi on the ground. After landing you switch to them to get directions to your parking spot, and before takeoff you talk to them to get permission to taxi to the runway.

Full Definition

The air traffic control position responsible for directing the movement of aircraft and vehicles on the airport's taxiways and other non-runway movement areas. Ground Control issues taxi instructions, clearances to cross runways, and coordinates surface traffic between gates, ramps, and runway . It operates on a published separate from (which the runways themselves).