memorial tablet vs plaque

memorial tablet and plaque both are nouns.

Word	Noun	Adjective	Verb	Adverb
memorial tablet	Yes	No	No	No
plaque	Yes	No	No	No

As nouns, memorial tablet and plaque are synonyms defined as:

Other synonyms of memorial tablet include brass.

memorial tablet (noun)	plaque (noun)
a memorial made of brass	a memorial made of brass
	(pathology) a small abnormal patch on or inside the body