RC means radio controlled. Vehicles used in an RC race are controlled by handheld radio controllers.
Originally starting in the 1940s, spin dizzies and tether cars hit the market but were only able to run in a circle from a tether. R/C cars started in the mid-sixties. Pioneers made 1/8th scale pan cars using .19-cubic-inch 2-stroke model airplane engines,
The 70's was the era of 1/8th scale "gas" powered R/C cars. Cars in the 70's were designed to run on-road, such as smooth parking lots.  In 1979, the Tamiya Rough Rider brought a new dimension to the hobby. The car was capable of running in off-road conditions such as dirt, rocky terrain, and water. It had a die-cast suspension system and large rubber tires. The Tamiya Sand Scorcher was released right after that and now sometimes fetching over a thousand dollars in eBay to collectors.
The 80's saw an explosion in the popularity of the hobby, most notably in the 1/10th scale off-road category. This was an era when you could expect to see 400 competitors in a major race. In 1985, Tamiya surprised everyone by introducing a 4-wheel drive (4WD) buggy called the HotShot. This was the first true off-road racing car from Tamiya. It was faster than its 2WD predecessors, especially in slippery and dusty conditions.Â
The 90's brought speed.  Kent Clausen drove an electric RC10L to a staggering speed of 70.1 mph at a bicycle track. This heralded a new type of racing, Superspeedway. Tamiya started to introduce scale and realistic looking cars similar to real cars that we drive everyday. These would eventually lead to the popularity of "touring" cars in the year 2000.
