steam line vs pipage

steam line and pipage both are nouns.

Word	Noun	Adjective	Verb	Adverb
steam line	Yes	No	No	No
pipage	Yes	No	No	No

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

steam line: a pipe conducting steam
pipage: a long tube made of metal or plastic that is used to carry water or oil or gas etc.

Other hypernyms of steam line include pipe, piping.

steam line (noun)	pipage (noun)
a pipe conducting steam	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