A trio sonata typically includes how many parts?

A trio sonata typically includes two melodic parts, which are often played by instruments such as violins or flutes, complemented by a basso continuo—a form of continuous bass accompaniment provided by instruments like a keyboard (harpsichord or organ) and a bass instrument (cello or bassoon). This setup creates a rich texture where the two higher parts engage in interplay and melodic dialogue while the basso continuo provides harmonic support and rhythmic foundation.

The essence of the trio sonata lies in its division of roles among the instruments, with the two soprano parts frequently working in counterpoint or harmony, while the basso continuo allows for flexibility in how the bass line is realized. This compositional structure became prominent during the Baroque period and showcases both the melodic and harmonic elements of ensemble playing.