What is the definition of a attending physician?

An Attending Physician is in charge of a particular patient's care and treatment. He/she is responsible for directing all care. In the USA, the attending physician is the same as your Primary Care Physician. However, in the US, many doctors have separated from having hospital privileges. They contract with a particular hospital physician or group of physicians to care for the attending's patients who are hospitalized. When the patient is discharged, the attending is again in charge of that patient's care (unless the two leave each other).