Why is the ninth month called September?
mid-13c., ferren, foreyne "out of doors," from Old French forain "strange, foreign; outer, external, outdoor; remote, out-of-the-way" (12c.), from Medieval Latin foranus "on the outside, exterior," from Latin foris "outside," literally "out of doors," related to for1s "door," from PIE *dhwor-ans-, from root *dhwer- "door, doorway" (see door). Spelling altered 17c. perhaps by influence of reign, sovereign. Replaced native fremd. Sense of "not in one's own land" is first attested late 14c.