Definition
The greatest horizontal distance at which prominent unlit objects can be seen and identified by day, or prominent lighted objects can be seen and identified by night, reported in statute miles, fractions of a mile, or feet (for runway visual range).
Plain English
How far you can clearly see. It's a measured distance — usually in miles — that tells pilots how clear the air is for spotting things like the ground, the runway, or other aircraft.
Context Anchor
Seen in aviation weather reports, airport information broadcasts, and notices to pilots when conditions affect how far pilots can see.
Derivation
Visibility comes from visible, which traces back to the Latin videre, meaning “to see.” That helps because the aviation meaning is about seeing distance, not just whether something is generally viewable.
Why Pilots Care
Visibility sets legal limits for VFR flight and determines whether you can navigate and land by eye or must rely on instruments.
Intuition Check
Visibility does not mean the same thing as clear skies. It means horizontal seeing distance; haze, smoke, rain, snow, or darkness can reduce visibility even when the clouds are not the main problem.
Example Sentence 1
The METAR reported visibility of 10 statute miles, well above the VFR minimum for the airspace.
Example Sentence 2
At night the pilot used the approach lights to judge visibility when deciding whether to land.