"alarm bell," 1586, from M.Fr. toquassen "an alarm bell, the ringing of an alarm bell" (1372), from O.Prov. tocasenh, from tocar "to strike" (from V.L. *toccare "strike a bell;" see touch) + senh "bell, bell note," from L.L. signum "bell, ringing of a bell," in L. "mark, signal." The current Eng. spelling is from 1794, adopted from modern Fr.