Hippopotamus \Hip`po*pot"a*mus\, n.; pl. E. Hippopotamuses, L. Hippopotami. [L., from Gr.?; "i`ppos horse + ? river. Cf. Equine.]

(Zo["o]l.) A large, amphibious, herbivorous mammal (Hippopotamus amphibius), common in the rivers of Africa. It is allied to the hogs, and has a very thick, naked skin, a thick and square head, a very large muzzle, small eyes and ears, thick and heavy body, and short legs. It is supposed to be the behemoth of the Bible. Called also zeekoe, and river horse. A smaller species (H. Liberiencis) inhabits Western Africa.

Source: Webster's Revised Unabridged Dictionary (1913)