A patient is any recipient of health care services performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, psychologist, dentist, veterinarian, or other health care provider.
The word patient originally meant 'one who suffers'. This English noun comes from the Latin word patiens, the present participle of the deponent verb, patior, meaning 'I am suffering,' and akin to the Greek verb ? (= paskhein, to suffer) and its cognate noun (= pathos).
An outpatient (or out-patient) is a patient who is hospitalized for less than 24 hours. Even if the patient will not be formally admitted with a note as an outpatient, they are still registered, and the provider will usually give a note explaining the reason for the service, procedure, scan, or surgery, which should include the names and titles and IDs of the participating personnel, the patient's name and date of birth and ID and signature of informed consent, estimated pre- and post-service time for a history and exam (before and after), any anesthesia or medications needed, and estimated time of discharge absent any (further) complications. Treatment provided in this fashion is called ambulatory care. Sometimes surgery is performed without the need for a formal hospital admission or an overnight stay. This is called outpatient surgery. Outpatient surgery has many benefits, including reducing the amount of medication prescribed and using the physician's or surgeon's time more efficiently. More procedures being performed in a surgeon's office, termed office-based surgery, rather than in a hospital-based operating room. Outpatient surgery is suited best for healthy patients undergoing minor or intermediate procedures (limited urologic, ophthalmologic, or ear, nose, and throat procedures and procedures involving the extremities).
An inpatient (or in-patient), on the other hand, is "admitted" to the hospital and stays overnight or for an indeterminate time, usually several days or weeks, though in some extreme cases, such as with coma or persistent vegetative state, patients can stay in hospitals for years, sometimes until death. Treatment provided in this fashion is called inpatient care. The admission to the hospital involves the production of an admission note. The leaving of the hospital is officially termed discharge, and involves a corresponding discharge note.
Misdiagnosis is the leading cause of medical error in outpatient facilities. Ever since the National Institute of Medicine's groundbreaking 1999 report, "To Err is Human", found up to 98,000 hospital patients die from preventable medical errors in the U.S. each year, government and private sector efforts have focused on inpatient safety. While patient safety efforts have focused on inpatient hospital settings for more than a decade, medical errors are even more likely to happen in a doctor's office or outpatient clinic or center.
A day patient or (day-patient) is a patient who is using the full range of services of a hospital or clinic, but is not expected to stay the night. The term was originally used by psychiatric hospital services using of this patient type to care for people needing support to make the transition from in-patient to out-patient care. However, the term is now also heavily used for people attending hospitals for day surgery.
Because of concerns such as dignity, human rights and political correctness, the term "patient" is not always used to refer to a person receiving health care. Other terms that are sometimes used include health consumer, health care consumer, customer or client. However, such terminology may be offensive to those receiving public health care as it implies a business relationship.
In veterinary medicine, the client is the owner or guardian of the patient. These may be used by governmental agencies, insurance companies, patient groups, or health care facilities. Individuals who use or have used psychiatric services may alternatively refer to themselves as consumers, users, or survivors.
In nursing homes and assisted living facilities, the term resident is generally used in lieu of patient, but it is common for staff members at such a facility to use the term patient in reference to residents. Similarly, those receiving home health care are called clients.
The examples and perspective in this section deal primarily with the United Kingdom and do not represent a worldwide view of the subject. (June 2015) (Learn how and when to remove this template message)
The doctor-patient relationship has sometimes been characterized as silencing the voice of patients. It is now widely agreed that putting patients at the centre of healthcare by trying to provide a consistent, informative and respectful service to patients will improve both outcomes and patient satisfaction. 
When patients are not at the centre of healthcare, when institutional procedures and targets eclipse local concerns, then patient neglect is possible. Incidents in the UK, such as the Stafford Hospital scandal and the Winterbourne View hospital abuse scandal, have shown the dangers of ignoring patient concerns. Investigations into these and other similar scandals have recommended that the health service put patient experience at the heart of what it does, and especially that patients themselves are heard loud and clear within the health services.
There are many reasons for why health services should listen more to patients. Patients spend more time in healthcare services than regulators or quality controllers, and can recognize problems such as service delays, poor hygiene, and poor conduct. Patients are particularly good at identifying soft problems, such as attitudes, communication, and 'caring neglect', that are difficult to capture with institutional monitoring.
One important way in which patients can be placed at the centre of healthcare is for health services to be more open about patient complaints. Each year many hundreds of thousands of patients complain about the care they have received, and these complaints contain valuable information for any health services which want to learn about and improve patient experience