英语词源字典 - 在线词源网站

entrench (v.)[entrench 词源字典]: also intrench, 1550s, implied in intrenched, from en- (1) "make, put in" + trench (n.). Figurative use is from 1590s. Related: Entrenched; entrenching.[entrench etymology, entrench origin, 英语词源]
no-man's-land (n.): 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."