briard vs shepherd dog

briard and shepherd dog both are nouns.

Word	Noun	Adjective	Verb	Adverb
briard	Yes	No	No	No
shepherd dog	Yes	No	No	No

As nouns, shepherd dog is a hypernym of briard; that is, shepherd dog is a word with a broader meaning than briard:

briard: old French breed of large strong usually black dogs having a long tail and long wavy and slightly stiff coat
shepherd dog: any of various usually long-haired breeds of dog reared to herd and guard sheep

Other hypernyms of briard include sheep dog, sheepdog.

briard (noun)	shepherd dog (noun)
old French breed of large strong usually black dogs having a long tail and long wavy and slightly stiff coat	any of various usually long-haired breeds of dog reared to herd and guard sheep