Plain English Meaning
The lowest altitude you are allowed to fly on a charted route that still keeps you safely above terrain and obstacles for the whole segment, but is only valid when you are within 22 nautical miles of the navigation station.
Full Definition
The lowest published altitude on a Victor airway, jet route, or other charted route segment that meets obstacle clearance requirements for the entire segment, but only assures acceptable navigation signal coverage from the route's navigation aids within 22 nautical miles of the station. Pilots may use this altitude only within 22 NM of the VOR.
Context Anchor
Seen on IFR en route charts and in instrument route planning, often shown as for a segment between .