reflectivity vs reflectance

reflectivity and reflectance both are nouns.

Word	Noun	Adjective	Verb	Adverb
reflectivity	Yes	No	No	No
reflectance	Yes	No	No	No

As nouns, reflectivity and reflectance are synonyms defined as:

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

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

reflectivity (noun)	reflectance (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