reflectance

noun

re·​flec·​tance ri-ˈflek-tən(t)s 

: the fraction of the total radiant flux incident upon a surface that is reflected and that varies according to the wavelength distribution of the incident radiation

The basis of this approach is that different materials exhibit unique reflectance and emission properties as a function of wavelength across the electromagnetic spectrum.

—Jeffrey Star and John Estes

broadly, nontechnically : reflectivity

screen reflectance

compare albedo

Examples of reflectance in a Sentence

Recent Examples on the Web

In one study, researchers used UV reflectance analysis to observe whether applying moisturizing cream before or after sunscreen impacted the sunscreen's effectiveness. —Anna Giorgi, Verywell Health, 30 Sep. 2025

The ‘red edge’ was a term coined by Carl Sagan when measuring our planet’s surface reflectance spectrum during NASA’s Galileo spacecraft’s Earth fly-by, says Duffy. —Bruce Dorminey, Forbes.com, 15 Sep. 2025

Low-sloped roofs for commercial and multi-family buildings will no longer be required to use energy-saving solar reflectance. —Kelly Puente, The Tennessean, 5 June 2025

In addition to multispectral imaging, the researchers also used X-ray fluorescence, which surveys elemental composition, and fiber-optic reflectance spectroscopy, which analyzes pigments. —Sonja Anderson, Smithsonian Magazine, 26 Mar. 2025

Word History

First Known Use

1893, in the meaning defined above

Medical Definition

reflectance

noun

re·​flec·​tance ri-ˈflek-tən(t)s 

: the fraction of the total radiant flux incident upon a surface that is reflected and that varies according to the wavelength distribution of the incident radiation

called also reflection coefficient, reflection factor