remembrance vs retention

remembrance and retention both are nouns.

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

As nouns, retention is a hypernym of remembrance; that is, retention is a word with a broader meaning than remembrance:

Other hypernyms of remembrance include memory, retentiveness, retentivity.

remembrance (noun)	retention (noun)
the ability to recall past occurrences	the act of retaining something
a recognition of meritorious service	the power of retaining liquid
	the power of retaining and recalling past experience