TOCSIN, a signal of alarm given by the ringing of a bell, hence any warning or danger signal. The earliest form in English is tocksaine, which was borrowed from the O. Fr. toquesin (toquer, to strike, cf. toucher and sin, mod. signe, a signal, Lat. signum). The use of " touch " and its cognate forms with the idea of giving a sound is seen in " tucket," Ital. toccata, which probably originally meant a signal given by tap of drum, but is always applied to a flourish or fanfare on a trumpet.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)