visibility

n. quality of being clearly seen; distance to which one can see clearly (Meteorology); state or quality of providing an unobstructed view

In meteorology, visibility is a measure of the distance at which an object or light can be clearly discerned. It is important to all forms of traffic: roads, sailing and aviation. Meteorological visibility refers to transparency of air: in dark, meteorological visibility is still the same as in daylight for the same air. Aviation. In aviation, visibility is defined as the greater of:a) the greatest distance at which a black object of suitable dimensions, situated near the ground, can be seen and recognized when observed against a bright background;b) the greatest distance at which lights of 1,000 candelas can be seen and identified against an unlit background.
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(n.)
The quality or state of being visible.
  

Noun
1. quality or fact or degree of being visible; perceptible by the eye or obvious to the eye; "low visibility caused by fog"
(synonym) visibleness
(antonym) invisibility, invisibleness
(hypernym) perceptibility
(hyponym) conspicuousness
2. degree of exposure to public notice; "that candidate does not have sufficient visibility to win an election"; "he prefers a low profile"
(synonym) profile
(hypernym) salience, saliency, strikingness
3. capability of providing a clear unobstructed view; "a windshield with good visibility"
(hypernym) clearness, clarity, uncloudedness