What is "dawn horse"

eohippus \eo*hip"pus\ ([=e]`[-o]*h[i^]p"p[u^]s), n. [Gr. 'hw`s dawn + "ipposhorse.] an extinct primitive dog-sized 4-toed Eocene mammal, the earliest horse known in the line of descent of the modern horse. It is classed in the extinct genus Hydracotherium. Called also dawn horse.

Syn: dawn horse.

n. earliest horse; extinct primitive dog-sized 4-toed Eocene animal [syn: eohippus]