Английский Этимологический словарь - tattoo (1)

- "signal," 1688, "signal calling soldiers or sailors to quarters at night," earlier tap-to (1644, in order of Col. Hutchinson to garrison of Nottingham), from Du. taptoe, from tap "faucet of a cask" (see tap (2)) + toe "shut." So called because police used to visit taverns in the evening to shut off the taps of casks. Hence, Devil's tattoo "action of idly drumming fingers in irritation or impatience."