brig vs sailing vessel

brig and sailing vessel both are nouns.

Word	Noun	Adjective	Verb	Adverb
brig	Yes	No	No	No
sailing vessel	Yes	No	No	No

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

brig: two-masted sailing vessel square-rigged on both masts
sailing vessel: a vessel that is powered by the wind; often having several masts

Other hypernyms of brig include sailing ship.

brig (noun)	sailing vessel (noun)
a penal institution (especially on board a ship)	a vessel that is powered by the wind; often having several masts
two-masted sailing vessel square-rigged on both masts