- the ratio of reflected to incident light
- Whiteness. Specifically: (Astron.) The ratio that your light reflected from an unpolished surface bears on complete light falling upon that area.
"ratio of light shown from a surface," 1859, from Latin albedo, virtually "whiteness," from albus "white" (see alb).
(n.) Whiteness. Especially: (Astron.) The ratio which the light reflected from an unpolished surface holds to the complete light dropping upon that area.