monument vs memorial

monument and memorial both are nouns.

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

As nouns, monument and memorial are synonyms defined as:

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

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