Plain English Meaning
A company that runs the communication network airlines and pilots use to send messages and voice calls between aircraft and the people on the ground who need to hear from them.
Full Definition
A private company that provides communication services and infrastructure to the aviation industry, including long-range HF and VHF radio links, datalink services, and message handling between aircraft and airline operations or air traffic facilities.
Context Anchor
Seen in instrument departure discussions when a clearance or message may be delivered through an aviation communication service rather than spoken directly over the tower frequency.