retention vs memory

retention and memory both are nouns.

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

As nouns, retention and memory are synonyms defined as:

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

Other synonyms of retention include retentiveness, retentivity.

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