nacre vs mother-of-pearl

nacre and mother-of-pearl both are nouns.

Word	Noun	Adjective	Verb	Adverb
nacre	Yes	No	No	No
mother-of-pearl	Yes	No	No	No

As nouns, nacre and mother-of-pearl are synonyms defined as:

nacre and mother-of-pearl: the iridescent internal layer of a mollusk shell

nacre (noun)	mother-of-pearl (noun)
the iridescent internal layer of a mollusk shell	the iridescent internal layer of a mollusk shell