refractory pot vs vessel

refractory pot and vessel both are nouns.

Word	Noun	Adjective	Verb	Adverb
refractory pot	Yes	No	No	No
vessel	Yes	No	No	No

As nouns, vessel is a hypernym of refractory pot; that is, vessel is a word with a broader meaning than refractory pot:

refractory pot: a small porous bowl made of bone ash used in assaying to separate precious metals from e.g. lead
vessel: an object used as a container (especially for liquids)

refractory pot (noun)	vessel (noun)
a small porous bowl made of bone ash used in assaying to separate precious metals from e.g. lead	a craft designed for water transportation
	an object used as a container (especially for liquids)
	a tube in which a body fluid circulates