"one who practices osteopathy," by 1897, a back-formation from osteopathy.
Entries linking to osteopath
osteopathy n.
1857, "disease of the bones," from Greek osteon "bone" (from PIE root *ost- "bone") + -pathy "disorder, disease," from Greek -patheia, combining form of pathos "suffering, disease, feeling" (from PIE root *kwent(h)- "to suffer"). As a system of treating ailments by the manipulation of bones, it dates from 1889.