This is incorrect. You are likely confused due to the fact that the names of the fields are similar.
Osteopathy /=/ osteopathic
I'll discuss the fields as the are in the US, as I am not aware of how they are in other countries.
Chiropractors go through their own degree programs through their own colleges.
Osteopaths are homeopathic practitioners (not doctors, and they refer to their customers as clients, they are legally not allowed to refer to them as patients) and are alternative medicine practicioners.
MDs receive a medical degree and are doctors.
DOs receive a medical degree (an MD) as well as an additional 300+ hours of osteopathic study through their medical school to receive a second medical degree certification - this is NOT the same as the homeopathic study, this is the study of the bones, joints, nerves, and how they all work together as a whole.