‖n. [ NL., from E. Siva + Gr. &unr_;&unr_;&unr_;&unr_; a beast, an animal. ] (Paleon.) A genus of very large extinct ruminants found in the Tertiary formation of India. The snout was prolonged in the form of a proboscis. The male had four horns, the posterior pair being large and branched. It was allied to the antelopes, but very much larger than any exsisting species. [ 1913 Webster ]