coefficient of reflection vs reflectance

coefficient of reflection and reflectance both are nouns.

Word	Noun	Adjective	Verb	Adverb
coefficient of reflection	Yes	No	No	No
reflectance	Yes	No	No	No

As nouns, coefficient of reflection and reflectance are synonyms defined as:

coefficient of reflection and reflectance: the fraction of radiant energy that is reflected from a surface

Other synonyms of coefficient of reflection include reflection factor, reflectivity.

coefficient of reflection (noun)	reflectance (noun)
the fraction of radiant energy that is reflected from a surface	the fraction of radiant energy that is reflected from a surface