(Fr. cadence parfaite, cadence authentique; Ger. Ganzschluss, vollkommene Kadenz; It. cadenza perfetta, cadenza intera).
A Cadence consisting of a dominant chord followed by a tonic chord (V–I), normally both in root position. In some theoretical writings the term is extended to cover any cadence ending on the tonic, thus including the plagal form (IV–I) as well as the ‘authentic’ form; particularly in American writings, it is sometimes specified that a cadence is not ‘perfect’ unless the uppermost voice sounds the tonic note in the final chord.
Julian Rushton