cupel vs bone-ash cup

cupel and bone-ash cup both are nouns.

Word	Noun	Adjective	Verb	Adverb
cupel	Yes	No	No	No
bone-ash cup	Yes	No	No	No

As nouns, cupel and bone-ash cup are synonyms defined as:

cupel and bone-ash cup: a small porous bowl made of bone ash used in assaying to separate precious metals from e.g. lead

Other synonyms of cupel include refractory pot.

cupel (noun)	bone-ash cup (noun)
a small porous bowl made of bone ash used in assaying to separate precious metals from e.g. lead	a small porous bowl made of bone ash used in assaying to separate precious metals from e.g. lead