Official Aviation Definition
A VHF Omnidirectional Range (VOR) is a terrestrial ground-based radio navigation beacon operating in the very high frequency (VHF) band between 108.0 and 117.95 MHz. It transmits 360 radial signals aligned with magnetic north, allowing cockpit instruments to determine the aircraft bearing to or from the station.
In Simple Words
A ground radio navigation lighthouse that sends out 360 invisible spokes in every direction so pilots know exactly which angle they are from the station.
Real-World Flight Example
The flight crew tracked the 240-degree radial inbound to the Santa Monica VOR at 5,000 feet.