Definition
The air traffic control position at a tower-controlled airport responsible for directing the movement of aircraft and authorized vehicles on the airport movement area, excluding active runways. Ground Control issues taxi instructions, route assignments, and clearances to cross or hold short of taxiways and runways, and coordinates with the tower (Local Control) before any aircraft enters or crosses an active runway.
Plain English
The controller who tells you how to taxi around the airport. They handle everything happening on the taxiways and ramps. The tower controller handles the runways themselves.
Context Anchor
In an IFR control sequence, pilots usually contact Ground Control after receiving a clearance and before taxiing, or after landing when leaving the runway and taxiing to parking.
Derivation
Named for what it controls: aircraft on the ground, as opposed to aircraft in the air. The 'control' part comes from air traffic control's core function -- separating traffic and issuing instructions to keep movements orderly and safe.
Why Pilots Care
Contacting the correct Ground Control frequency prevents runway incursions and keeps surface traffic moving safely and efficiently.
Intuition Check
Ground Control does not mean someone is controlling the airplane for you. It means the ATC position that gives instructions for moving on the airport surface.
Example Sentence 1
After starting the engine, the pilot called Ground Control and requested taxi to runway 27.
Example Sentence 2
Ground Control cleared the aircraft to taxi via Alpha to the east ramp.