reflectivity vs coefficient of reflection

reflectivity and coefficient of reflection both are nouns.

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

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

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

Other synonyms of reflectivity include reflectance, reflection factor.

reflectivity (noun)	coefficient of reflection (noun)
the ability to reflect beams or rays	the fraction of radiant energy that is reflected from a surface
the capability of quiet thought or contemplation
the fraction of radiant energy that is reflected from a surface