FLAG, n. A colored rag borne above troops and hoisted on forts and ships. It appears to serve the same purpose as certain signs that one sees and vacant lots in London -- Rubbish may be shot here.
Source: The Devil's Dictionary, 1911.
-- Ambrose Bierce, (Jun 24 1842-1914), US journalist, short-story writer; He was a noted wit, satirist and sardonic short story writer who disappeared while covering the Mexican revolution.