[ri-flek-tuh ns]

noun Physics, Optics.

the ratio of the intensity of reflected radiation to that of the radiation incident on a surface.

Compare albedo.

Origin of reflectance

First recorded in 1925–30; reflect + -ance Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for reflectance


reflection factor


a measure of the ability of a surface to reflect light or other electromagnetic radiation, equal to the ratio of the reflected flux to the incident fluxSymbol: ρ Compare transmittance, absorptance
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