electric furnace vs furnace

electric furnace and furnace both are nouns.

Word	Noun	Adjective	Verb	Adverb
electric furnace	Yes	No	No	No
furnace	Yes	No	No	No

As nouns, furnace is a hypernym of electric furnace; that is, furnace is a word with a broader meaning than electric furnace:

electric furnace: any furnace in which the heat is provided by an electric current
furnace: an enclosed chamber in which heat is produced to heat buildings, destroy refuse, smelt or refine ores, etc.

electric furnace (noun)	furnace (noun)
any furnace in which the heat is provided by an electric current	an enclosed chamber in which heat is produced to heat buildings, destroy refuse, smelt or refine ores, etc.