no-man's-land (n.)

also no man's land, "terrain between front lines of entrenched armies," 1908, popularized in World War I; earlier a tract or district to which no one has an established claim; a region which is the subject of dispute between two parties" (by 1876). Nonemanneslond (early 14c.) was the name given to an unowned waste ground outside the north wall of London, the site of executions. No man (Old English nanne mon) was an old way of saying "nobody."