Cetancodontamorpha is a total clade of artiodactyls defined, according to Spaulding et al., as "Cetancodonta plus all extinct taxa more closely related to extant members of Cetancodonta than to any other living species." Cetancodonta is the crown clade containing Cetacea

Cetacea

The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises. Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal", was more general. It comes from Ancient Greek , meaning "whale" or "any huge fish or sea...

 (whales, dolphins, etc.) and hippopotamus

Hippopotamus

The hippopotamus , or hippo, from the ancient Greek for "river horse" , is a large, mostly herbivorous mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae After the elephant and rhinoceros, the hippopotamus is the third largest land mammal and the heaviest...

es. According to Spaulding et al., members of the cetancodont stem group (i.e., "stem-cetancodonts") include such taxa as Entelodontidae and Andrewsarchus.