Day's journey
Easton, 1897
The usual length of a day's journey in the East, on camel or horseback, in six or eight hours, is about 25 or 30 miles. The "three days' journey" mentioned in Exodus 3:18 is simply a journey which would occupy three days in going and returning.
Dictionary: M. G. Easton, Illustrated Bible Dictionary (1897, public domain).