memorial vs monument

memorial and monument both are nouns.

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

As nouns, memorial and monument are synonyms defined as:

memorial and monument: a structure erected to commemorate persons or events

memorial (noun)	monument (noun)
a structure erected to commemorate persons or events	a structure erected to commemorate persons or events
a recognition of meritorious service	a burial vault (usually for some famous person)
a written statement of facts submitted in conjunction with a petition to an authority	an important site that is marked and preserved as public property