An outpatient is a patient who is not hospitalized overnight but who visits a hospital, clinic, or associated facility for diagnosis or treatment. Treatment provided in this fashion is called ambulatory care. Outpatient surgery eliminates inpatient hospital admission, reduces the amount of medication prescribed, and uses a doctor's time more efficiently. More procedures are now being performed in a surgeon's office, termed office-based surgery, rather than in an operating room. Outpatient surgery is suited best for healthy people undergoing minor or intermediate procedures (limited urologic, ophthalmologic, or ear, nose, and throat procedures and procedures involving the extremities). http://en.wikipedia.org/wiki/Patient

A patient is any person who receives medical attention, care, or treatment. The person is most often ill or injured and in need of treatment by a physician or other health care professional, although one who is visiting a physician for a routine check-up may also be viewed as a patient. http://en.wikipedia.org/wiki/Patient

A clinic (or an outpatient clinic) is a small private or public health facility that is devoted to the care of outpatients, often in a community, in contrast to larger hospitals, which also treat inpatients. Some grow to be institutions as large as major hospitals, whilst retaining the name clinic. These are often associated with a hospital or medical school. http://en.wikipedia.org/wiki/Clinics