bone-ash cup vs refractory pot

bone-ash cup and refractory pot both are nouns.

Word	Noun	Adjective	Verb	Adverb
bone-ash cup	Yes	No	No	No
refractory pot	Yes	No	No	No

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

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

Other synonyms of bone-ash cup include cupel.

bone-ash cup (noun)	refractory pot (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