Before 1940, the term "jeep" was used by the U.S. Army as slang for new recruits or vehicles, but in 1941 the Jeep that went into production for World War II specifically tied the name to this light military 4x4, making it one of the oldest four-wheel drive mass-production vehicles now known as SUVs. The Jeep became the primary light 4-wheel-drive vehicle of the United States Armed Forces and the Allies during World War II and the postwar period, and the term "jeep" became common worldwide in the wake of the war. The Jeep marque has been headquartered in Toledo, Ohio, since Willys-Overland launched production of the first CJ or Civilian Jeep branded models there in 1945. The Jeep Wrangler series has remained in production since 1986 and is as central to the brand's identity as the 911 is to Porsche. The term "jeep" continues to be used as a generic term for vehicles inspired by the Jeep that are suitable for use on rough terrain.