reflectance vs reflectivity

reflectance and reflectivity both are nouns.

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

As nouns, reflectance and reflectivity are synonyms defined as:

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

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

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