👉 A piazzetta is a type of music notation used in Italian opera, particularly in the Baroque period. It is often used to indicate the key signature and note positions in an opera's score. In a piazzetta, the notes are written with four lines: the first line for the key signature (C, D, E, F), the second line for the major third (G, A#, Bb), the third line for the minor third (B, C#