liner vs furnace lining

liner and furnace lining both are nouns.

Word	Noun	Adjective	Verb	Adverb
liner	Yes	No	No	No
furnace lining	Yes	No	No	No

As nouns, furnace lining is a hyponym of liner; that is, furnace lining is a word with a more specific, narrower meaning than liner:

liner: a protective covering that protects an inside surface
furnace lining: lining consisting of material with a high melting point; used to line the inside walls of a furnace

Other hyponyms of liner include brake lining, bushing, cylindrical lining, facing, refractory.

liner (noun)	furnace lining (noun)
(baseball) a hit that flies straight out from the batter	lining consisting of material with a high melting point; used to line the inside walls of a furnace
a large commercial ship (especially one that carries passengers on a regular schedule)
a piece of cloth that is used as the inside surface of a garment
a protective covering that protects an inside surface