exhaust pipe vs pipage

exhaust pipe and pipage both are nouns.

Word	Noun	Adjective	Verb	Adverb
exhaust pipe	Yes	No	No	No
pipage	Yes	No	No	No

As nouns, pipage is a hypernym of exhaust pipe; that is, pipage is a word with a broader meaning than exhaust pipe:

exhaust pipe: a pipe through which burned gases travel from the exhaust manifold to the muffler
pipage: a long tube made of metal or plastic that is used to carry water or oil or gas etc.

Other hypernyms of exhaust pipe include pipe, piping.

exhaust pipe (noun)	pipage (noun)
a pipe through which burned gases travel from the exhaust manifold to the muffler	a long tube made of metal or plastic that is used to carry water or oil or gas etc.
	a fee charged for the use of pipes