Parasang n. : A Persian measure of length, which, according to Herodotus and Xenophon, was thirty stadia, or somewhat more than three and a half miles. The measure varied in different times and places, and, as now used, is estimated at from three and a half to four English miles.

Example:


Taxonomy
parasang, farsakh, Herodotus, paces, free encyclopedia, Xenophon, farsang, parasanga, Arabic, stadia, History, Old Iranian languages, Iranian languages, 1st century, stades, Cambridge history of Iran, units of measure, New Persian.

Defination from the web:
parasang is a historical Iranian unit of itinerant distance comparable to the European league. ... The parasang may have originally been some fraction of the distance an infantryman could march in some predefined period of time. ...