the world > movement > motion in a certain direction > backward movement > move backwards [verb (reflexive)] > turn back or reverse course (3)
transitive (reflexive). To turn or face the other way (usually in order to go back); = senses 2b 1. Now rare.
transitive (reflexive). To turn oneself so as to face or go in the opposite direction; = sense 2b.
intransitive. To turn again; to turn back.