Plain English Meaning
It is the runway visibility measurement taken at the part of the runway where the aircraft will land. The number tells the pilot how far they will be able to see along the runway when they touch down.
Full Definition
The Runway Visual Range (RVR) value reported by the transmissometer or visibility sensor located near the touchdown zone of the runway, representing the horizontal distance a pilot can see down the runway from the approach end where the aircraft is expected to touch down.
Context Anchor
Seen in low-visibility weather reports, instrument approach information, and landing minimums for runways equipped with RVR reporting.