vent-hole vs blowhole

vent-hole and blowhole both are nouns.

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

As nouns, vent-hole and blowhole are synonyms defined as:

Other synonyms of vent-hole include vent, venthole.

vent-hole (noun)	blowhole (noun)
a hole for the escape of gas or air	a hole for the escape of gas or air
	the spiracle of a cetacean located far back on the skull