hippopotamus vs Hippopotamus amphibius

hippopotamus and Hippopotamus amphibius both are nouns.

Word	Noun	Adjective	Verb	Adverb
hippopotamus	Yes	No	No	No
Hippopotamus amphibius	Yes	No	No	No

As nouns, hippopotamus and Hippopotamus amphibius are synonyms defined as:

hippopotamus and Hippopotamus amphibius: massive thick-skinned herbivorous animal living in or around rivers of tropical Africa

Other synonyms of hippopotamus include hippo, river horse.

hippopotamus (noun)	Hippopotamus amphibius (noun)
massive thick-skinned herbivorous animal living in or around rivers of tropical Africa	massive thick-skinned herbivorous animal living in or around rivers of tropical Africa