Orohippus, a prehistoric horse species that lived approximately 35 million years ago, is a fascinating creature that has intrigued scientists and historians. The word Orohippus is derived from Greek, meaning 'mountain horse.' However, there are several synonyms used interchangeably to describe this species, such as Epihippus, Hyracotherium, and Prodonttherium. The term Epihippus, meaning 'near horse,' is used to describe the horse's close evolutionary relation to modern-day horses. On the other hand, the term Hyracotherium means 'weasel beast,' implying that this species was small and agile. Finally, the term Prodonttherium means 'forward-pointing teeth,' referring to the horse's distinct dental structure. These different synonyms reflect the evolutionary traits and significance of this ancient horse species.