Definition
A ground-based radio navigation station that transmits signals in every direction, allowing a properly equipped aircraft to determine its bearing to or from the station along any of 360 selectable courses (radials). In civil aviation this almost always refers to the VHF Omnidirectional Range (VOR), which operates on frequencies between 108.0 and 117.95 MHz.
Plain English
A radio station on the ground that sends out signals in all directions. An aircraft receiver can tune in and read which direction the station is from the aircraft, which lets the pilot fly toward it, away from it, or along a chosen line through it.
Context Anchor
Seen in navigation instrument discussions, especially when learning how VOR navigation equipment shows the pilot a course to or from a ground station.
Derivation
Omni-' comes from Latin omnis meaning 'all,' and 'directional' refers to direction. 'Range' here is the older navigation sense of a radio station that defines lines of position, not the everyday sense of distance. So the name simply describes a station that provides directional guidance in all directions at once.
Why Pilots Care
It provides reliable azimuth guidance that underpins most VOR airways and non-precision approaches.
Analogy
Picture a hub with lines reaching out in every direction, like spokes on a wheel. The aircraft receiver can identify which spoke it is on relative to the station.
Intuition Check
“Range” does not mean the distance the airplane can fly here. In this term, it means a radio navigation system or station used to help determine direction.
Example Sentence 1
The pilot tuned the omnidirectional range, identified the station's Morse code, and tracked inbound on the 090 radial.
Example Sentence 2
During the instrument flight, the crew cross-checked position using two omnidirectional range stations.