What term describes the measure of reflectivity of a surface?

The term that describes the measure of reflectivity of a surface is albedo. Albedo is defined as the ratio of the amount of light or radiation reflected by a surface to the total amount incident upon it. A high albedo indicates that a surface is very reflective, such as fresh snow or ice, whereas a low albedo suggests a surface absorbs most of the incoming light, like asphalt or dense forest.

Transmittance refers to the fraction of incident light that passes through a material, and absorbance is related to the fraction of light that is absorbed by a material instead of being reflected. Refraction, on the other hand, is the bending of light as it passes from one medium to another of different density. Each of these terms pertains to different properties of light interaction with materials, but albedo specifically focuses on reflectivity.