tractor vs bulldozer

tractor and bulldozer both are nouns.

Word	Noun	Adjective	Verb	Adverb
tractor	Yes	No	No	No
bulldozer	Yes	No	No	No

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

tractor: a wheeled vehicle with large wheels; used in farming and other applications
bulldozer: large powerful tractor; a large blade in front flattens areas of ground

Other hyponyms of tractor include dozer, skidder.

tractor (noun)	bulldozer (noun)
a wheeled vehicle with large wheels; used in farming and other applications	large powerful tractor; a large blade in front flattens areas of ground
a truck that has a cab but no body; used for pulling large trailers or vans