German shepherd vs German shepherd dog

German shepherd and German shepherd dog both are nouns.

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

As nouns, German shepherd and German shepherd dog are synonyms defined as:

German shepherd and German shepherd dog: breed of large shepherd dogs used in police work and as a guide for the blind

Other synonyms of German shepherd include alsatian, German police dog.

German shepherd (noun)	German shepherd dog (noun)
breed of large shepherd dogs used in police work and as a guide for the blind	breed of large shepherd dogs used in police work and as a guide for the blind