reflectance vs coefficient of reflection

reflectance and coefficient of reflection both are nouns.

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

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

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

Other synonyms of reflectance include reflection factor, reflectivity.

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