fuel line vs piping

fuel line and piping both are nouns.

Word	Noun	Adjective	Verb	Adverb
fuel line	Yes	No	No	No
piping	Yes	No	No	Yes

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

fuel line: a pipe that carries gasoline from a tank to a gasoline engine
piping: a long tube made of metal or plastic that is used to carry water or oil or gas etc.

Other hypernyms of fuel line include pipage, pipe.

fuel line (noun)	piping (noun)
a pipe that carries gasoline from a tank to a gasoline engine	playing a pipe or the bagpipes
	a long tube made of metal or plastic that is used to carry water or oil or gas etc.
	a thin strip of covered cord used to edge hems

fuel line (adverb)	piping (adverb)
	(used of heat) extremely