Definition
In aviation radio use, the specific channel — measured in megahertz (MHz) or kilohertz (kHz) — on which a radio transmits and receives. Each air traffic facility, navigation aid, and service is assigned its own frequency so that pilots and controllers can communicate without interference.
Plain English
The radio channel you tune to in order to talk to a particular controller or listen to a particular service.
Context Anchor
Pilots see FREQ on charts, airport information, notices, flight planning material, and radio equipment.
Derivation
From the Latin 'frequens' meaning 'crowded' or 'repeated often.' In radio, it refers to how often the radio wave repeats per second — higher frequency means more repetitions per second. That repetition rate is what defines each separate channel.
Why Pilots Care
Correct frequency selection ensures reliable two-way communication with controllers and prevents missed clearances or instructions.
Analogy
It is like tuning a car radio to a specific station. If the number is wrong, the radio may work perfectly, but you still will not hear the station you wanted.
Intuition Check
Frequency does not mean how often you do something here. In this aviation context, it means the radio channel or signal setting to use.
Example Sentence 1
Approach told us to monitor the tower FREQ once we were inside five miles.