start back
To begin returning to some place. Let's start back now so we can get home before dinner. We started back before I had a chance to get any photos of the place.
start back (to some place)
to begin the journey back to a place. When do we start back to Chicago? It's time to start back.
start back
v. To begin a return journey: We had better start back soon or we won't get home before dark.