early 15c., "a drawing or pulling" (originally the pulling of a dislocated limb to reposition it), from Medieval Latin tractionem (nominative tractio) "a drawing" (mid-13c.), noun of action from past participle stem of Latin trahere "to pull, draw" (see tract (n.1)). Sense of "rolling friction of a vehicle" first appears 1825. In modern medical care, "a sustained pull to a part of the body to hold fractured bones in position," 1885.[traction etymology, traction origin, 英语词源]