1) Family hippopotamidae 2) Hippopotami 3) Mammal family 
Hippopotaminae Gray, 1821 †Kenyapotaminae Pickford, 1983 Hippopotamuses are stout, naked-skinned, and amphibious artiodactyl members (and the only living members) of the family Hippopotamidae possessing three-chambered stomachs and walking on four toes on each foot. While they resemble pigs physiologically, their closest living relatives are act...
Hippopotamidae is the hippopotamus family of animals of the order Artiodactyla.
[n] - hippopotami
family Hippopotamidae noun hippopotami