cask vs vessel

cask and vessel both are nouns.

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

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

cask (noun)	vessel (noun)
a cylindrical container that holds liquids	a craft designed for water transportation
the quantity a cask will hold	an object used as a container (especially for liquids)
	a tube in which a body fluid circulates