memory vs retention

memory and retention both are nouns.

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

As nouns, memory and retention are synonyms defined as:

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

Other synonyms of memory include retentiveness, retentivity.

memory (noun)	retention (noun)
an electronic memory device	the act of retaining something
the power of retaining and recalling past experience	the power of retaining liquid
the cognitive processes whereby past experience is remembered	the power of retaining and recalling past experience
something that is remembered
the area of cognitive psychology that studies memory processes