Definition
COM2 is the second of two VHF communication radios installed in an aircraft, used for voice communication with air traffic control, flight service stations, and other ground or airborne stations. It operates in the same VHF aviation band as COM1 (118.000–136.975 MHz) and provides a secondary, independently tunable radio so the pilot can monitor or transmit on a different frequency without retuning the primary radio.
Plain English
The second radio used for talking on the aviation airwaves. It works the same as the first one and lets the pilot have a second frequency ready to use.
Context Anchor
Seen on aircraft radio panels, avionics displays, and instrument flying discussions about communication equipment.
Derivation
COM' is short for 'communication.' The '2' simply indicates it is the second of the two communication radios in the aircraft, with COM1 being the primary.
Why Pilots Care
Provides a backup radio if the primary fails and allows monitoring two frequencies at once.
Intuition Check
COM2 does not mean a different kind of aviation communication. It means the second communication radio installed or displayed in the aircraft.
Example Sentence 1
While talking to approach control on COM1, the pilot tuned the tower frequency on COM2 so it was ready for the handoff.
Example Sentence 2
With COM1 experiencing static, the crew switched all calls to COM2.