burner vs gas burner

burner and gas burner both are nouns.

Word	Noun	Adjective	Verb	Adverb
burner	Yes	No	No	No
gas burner	Yes	No	No	No

As nouns, gas burner is a hyponym of burner; that is, gas burner is a word with a more specific, narrower meaning than burner:

burner: an apparatus for burning fuel (or refuse)
gas burner: burner such that combustible gas issues from a nozzle to form a steady flame

Other hyponyms of burner include blowlamp, blowtorch, torch, gas bracket, gas jet.

burner (noun)	gas burner (noun)
an apparatus for burning fuel (or refuse)	burner such that combustible gas issues from a nozzle to form a steady flame
the heating elements of a stove or range on which pots and pans are placed for cooking