Emily Dickinson Lexicon

SIV-A-THE'RI-UM, n. [Siva, an Indian deity, and Gr. θηριον, a wild animal.]

An extinct animal, whose skull and other bones were recently discovered in India, being before unknown. It had four horns and a proboscis; was larger than the rhinoceros, are must have resembled an immense antelope. – Mantell.