riser vs piping

riser and piping both are nouns.

Word	Noun	Adjective	Verb	Adverb
riser	Yes	No	No	No
piping	Yes	No	No	Yes

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

riser: a vertical pipe in a building
piping: a long tube made of metal or plastic that is used to carry water or oil or gas etc.

Other hypernyms of riser include pipage, pipe.

riser (noun)	piping (noun)
structural member consisting of the vertical part of a stair or step	playing a pipe or the bagpipes
a vertical pipe in a building	a long tube made of metal or plastic that is used to carry water or oil or gas etc.
a person who rises (especially from bed)	a thin strip of covered cord used to edge hems

riser (adverb)	piping (adverb)
	(used of heat) extremely