The word albedo is a general term for the ratio of reflected/scattered power to incident power,

(1)

It is also called then reflection coefficient. The albedo (sometimes called the simple albedo) is also given by

where is the emissivity. This is Kirchhoff's law.

For albedos of some common substances, see Rees (1990) and Weast (1981).

Substance/Object	Albedo
Enceladus	0.8
Europa	0.6
forest	0.05-0.10
granite	0.30-0.35
grass	0.05-0.30
Mars	0.25
Moon	0.12
sand	0.20-0.40
snow	0.6
soil	0.05-0.30
urban areas	0.05-0.20

There are a number of specific types of albedos with precise definitions.

Bond Albedo, Geometric Albedo, Intensity, Phase Function, Phase Integral, Single Scattering Albedo