Mobile Army Surgical Hospital
Mobile Army Surgical Hospitals (MASH) were U.S. Army field hospital units conceptualized in 1946 as replacements for the obsolete World War II-era Auxiliary Surgical Group hospital units. MASH units were in operation from the Korean War to the Gulf War before being phased out in the early 2000s, in favor of combat support hospitals.
Source: Wikipedia — Mobile Army Surgical Hospital (CC BY-SA 4.0)