smoke hole vs vent-hole

smoke hole and vent-hole both are nouns.

Word	Noun	Adjective	Verb	Adverb
smoke hole	Yes	No	No	No
vent-hole	Yes	No	No	No

As nouns, vent-hole is a hypernym of smoke hole; that is, vent-hole is a word with a broader meaning than smoke hole:

Other hypernyms of smoke hole include blowhole, vent, venthole.

smoke hole (noun)	vent-hole (noun)
a vent (as in a roof) for smoke to escape	a hole for the escape of gas or air