Medical evacuation, often shortened to medevac or medivac, is the timely and efficient movement and en route care provided by medical personnel to wounded being evacuated from a battlefield, to injured patients being evacuated from the scene of an accident to receiving medical facilities, or to patients at a rural hospital requiring urgent care at a better-equipped facility using medically equipped ground vehicles or aircraft.
Medical Evacuation (MEDEVAC) (documentary) by DEVGRU5022
Examples include civilian EMS vehicles, civilian aeromedical helicopter services, and Army air ambulances.
An ambulance is a vehicle for transportation of sick or injured people to, from or between places of treatment for an illness or injury, and in some instances will also provide out of hospital medical care to the patient.
Air medical services is a comprehensive term covering the use of air transportation, airplane or helicopter, to move patients to and from healthcare facilities and accident scenes.
5 Things You Don't Know About: Medical Evacuation by Military.com
This term also covers the transfer of patients from the battlefield to a treatment facility or from one treatment facility to another by medical personnel, such as from a local hospital to a trauma center.
A trauma center is a hospital equipped and staffed to provide care for patients suffering from major traumatic injuries such as falls, motor vehicle collisions, or gunshot wounds.