Definition
The portion of the electronic flight display or audio panel that shows the communication radio frequencies currently selected — typically displaying both the active frequency (the one being transmitted and received on) and the standby frequency (the next one tuned and ready to swap in).
Plain English
The small box on the screen that shows which radio frequencies you are using to talk to controllers — usually one you are using right now and one you have set up next.
Context Anchor
Seen on electronic flight displays and radio displays when checking or changing the aircraft’s communications radio frequency.
Derivation
‘COM’ is short for ‘communication.’ ‘Window’ is used in the display sense — a framed area on the screen showing specific information, like a window on a computer screen.
Why Pilots Care
It lets the pilot confirm and change communication frequencies without diverting attention from attitude and navigation information.
Intuition Check
Do not read “window” as a cockpit window. Here it means a labeled area on a display screen. Do not read “COM” as a computer port. Here it means the aircraft communications radio used for voice calls.
Example Sentence 1
She loaded the tower frequency into the standby side of the COM frequency window before contacting ground.
Example Sentence 2
After entering the new frequency, the COM frequency window updated to show it as active with the previous one now in standby.