What's the difference between i.e. and e.g.?
1580s, "system of military discipline," from Latin militia "military service, warfare," from miles "soldier" (see military). Sense of "citizen army" (as distinct from professional soldiers) is first recorded 1690s, perhaps from a sense in French cognate milice. In U.S. history, "the whole body of men declared by law amenable to military service, without enlistment, whether armed and drilled or not" (1777).