Plain English Meaning

A radio beacon on the ground that lets a pilot know which direction they are from it, measured around a full circle. The pilot picks a line out from the station and the cockpit instrument shows whether they are on that line, left of it, or right of it.

Full Definition

A ground-based radio navigation aid that transmits signals in the VHF band (108.0–117.95 MHz) allowing a suitably equipped aircraft to determine its bearing to or from the station along any of 360 selectable courses, called radials. The aircraft's VOR receiver compares two signals by the station — a signal and a variable signal — and the between them indicates the aircraft's from the station.