Why is the ninth month called September?
c.1200, "a defined course of traveling; one's path in life," from Old French journee "day's work or travel" (12c.), from Vulgar Latin diurnum "day," noun use of neuter of Latin diurnus "of one day" (see diurnal). Meaning "act of traveling by land or sea" is c.1300. In Middle English it also meant "a day" (c.1400); a day's work (mid-14c.); "distance traveled in one day" (mid-13c.), and as recently as Johnson (1755) the primary sense was still "the travel of a day."
mid-14c., "travel from one place to another," from Anglo-French journeyer, Old French journoier, from journee (see journey (n.)). Related: Journeyed; journeying.
(1.) A day's journey in the East is from 16 to 20 miles (Num. 11:31). (2.) A Sabbath-day's journey is 2,000 paces or yards from the city walls (Acts 1:12). According to Jewish tradition, it was the distance one might travel without violating the law of Ex. 16:29. (See SABBATH.)