Hipparion
Pronunciation : Hip*pa"ri*on
Part of Speech : n.
Etymology : [NL., fr. Gr. (Paleon.)
Definition : Defn: An extinct genus of Tertiary mammals allied to the horse, but three-toed, having on each foot a small lateral hoof on each side of the main central one. It is believed to be one of the ancestral genera of the Horse family.
Source : Webster's Unabridged Dictionary, 1913