retention vs retentivity

retention and retentivity both are nouns.

Word	Noun	Adjective	Verb	Adverb
retention	Yes	No	No	No
retentivity	Yes	No	No	No

As nouns, retention and retentivity are synonyms defined as:

Other synonyms of retention include retentiveness.

As nouns, retention and retentivity are synonyms defined as:

retention and retentivity: the power of retaining and recalling past experience

Other synonyms of retention include memory, retentiveness.

retention (noun)	retentivity (noun)
the act of retaining something	the power of retaining liquid
the power of retaining liquid	the property of retaining possessions that have been acquired
the power of retaining and recalling past experience	the power of retaining and recalling past experience