memorial vs message

memorial and message both are nouns.

Word	Noun	Adjective	Verb	Adverb
memorial	Yes	No	No	No
message	Yes	No	Yes	No

As nouns, message is a hypernym of memorial; that is, message is a word with a broader meaning than memorial:

memorial: a written statement of facts submitted in conjunction with a petition to an authority
message: content communicating a message; what something is about

Other hypernyms of memorial include content, subject matter, substance.

memorial (noun)	message (noun)
a structure erected to commemorate persons or events	content communicating a message; what something is about
a recognition of meritorious service	a communication (usually brief) that is written or spoken or signaled
a written statement of facts submitted in conjunction with a petition to an authority