Meaning of geographic range

ge'ograph'ic range'

Pronunciation: [key]
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  1. the distance at which a certain light, as that of a lighthouse, is visible to the eye at a given elevation, assuming that the weather is clear and that the light is sufficiently powerful to be visible from any point at which it appears above the horizon. Cf. luminous range.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.