memo vs aide-memoire

memo and aide-memoire both are nouns.

Word	Noun	Adjective	Verb	Adverb
memo	Yes	No	No	No
aide-memoire	Yes	No	No	No

As nouns, aide-memoire is a hyponym of memo; that is, aide-memoire is a word with a more specific, narrower meaning than memo:

memo: a written proposal or reminder
aide-memoire: a memorandum summarizing the items of an agreement (used especially in diplomatic communications)

Other hyponyms of memo include position paper.

memo (noun)	aide-memoire (noun)
a written proposal or reminder	a memorandum summarizing the items of an agreement (used especially in diplomatic communications)