sheepdog vs collie

sheepdog and collie both are nouns.

Word	Noun	Adjective	Verb	Adverb
sheepdog	Yes	No	No	No
collie	Yes	No	No	No

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

sheepdog: any of various usually long-haired breeds of dog reared to herd and guard sheep
collie: a silky-coated sheepdog with a long ruff and long narrow head developed in Scotland

sheepdog (noun)	collie (noun)
any of various usually long-haired breeds of dog reared to herd and guard sheep	a silky-coated sheepdog with a long ruff and long narrow head developed in Scotland