flagon vs vessel

flagon and vessel both are nouns.

Word	Noun	Adjective	Verb	Adverb
flagon	Yes	No	No	No
vessel	Yes	No	No	No

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

flagon: a large metal or pottery vessel with a handle and spout; used to hold alcoholic beverages (usually wine)
vessel: an object used as a container (especially for liquids)

flagon (noun)	vessel (noun)
a large metal or pottery vessel with a handle and spout; used to hold alcoholic beverages (usually wine)	a craft designed for water transportation
	an object used as a container (especially for liquids)
	a tube in which a body fluid circulates