DIATONICK, in music, (composed of two Greek words, viz. the preposition dia, signifying a transition from one thing to another, and the substantival tonos, importing a given degree of tension or musical note), is indifferently applied to a scale or gammut, to intervals of a certain kind, or to a species of music, whether in melody or harmony, composed of these intervals. Thus we say the diatonick series, a diatonick interval, diatonick melody or harmony. As the diato-
nick scale forms the system of diatonick music, and Diarra-
consists of diatonick intervals, it will be necessary, for
understanding the former, that we should explain the
latter. See INTERVAL.