no-man's-land (n.)youdaoicibaDictYouDict[no-man's-land 词源字典]
also no man's land, "terrain between front lines of entrenched armies," 1908, popularized in World War I; in use from at least early 14c. as Nonemanneslond, an unowned waste ground outside the north wall of London, site for executions. No man (Old English nanne mon) was an old way of saying "nobody."[no-man's-land etymology, no-man's-land origin, 英语词源]