black rat snake vs pilot blacksnake

black rat snake and pilot blacksnake both are nouns.

Word	Noun	Adjective	Verb	Adverb
black rat snake	Yes	No	No	No
pilot blacksnake	Yes	No	No	No

As nouns, black rat snake and pilot blacksnake are synonyms defined as:

black rat snake and pilot blacksnake: large harmless shiny black North American snake

Other synonyms of black rat snake include blacksnake, Elaphe obsoleta, mountain blacksnake.

black rat snake (noun)	pilot blacksnake (noun)
large harmless shiny black North American snake	large harmless shiny black North American snake