Outpatient: An individual (patient) who receives health care services (such as surgery) on an outpatient basis, meaning they do not stay overnight in a hospital or inpatient facility. Many insurance companies have identified a list of tests and procedures (including surgery) that will not be covered (paid for) unless they are performed on an outpatient basis. The term outpatient is also used synonymously with ambulatory to describe health care facilities where procedures are performed.