A piece in compound ternary form is a ternary piece in which at least one of its part can be subdivided into two or more parts:

An excellent example of this form is found in Baroque Suites where sometimes we found two dances (minuets, gavottes or bourrées) that are played following this order: I - II - I.

In this case, each dance is in binary form and we have a ternary form (A - B - A) in which each dance is subdivided into two parts:

---

---