It is traditionally understood that GMC stands for General Motors Corporation. And that is mostly correct. As a division of General Motors, it has actually come to stand for General Motors Truck Company, as their focus is almost exclusively on the production of larger vehicles, such as trucks, buses, SUVs and pickups for personal and commercial use.
GMC started life as the Rapid Motor Vehicle Company back in 1902 by the truck builders and brothers Morris and Max Grabowsky. This is why you will sometimes hear that GMC actually stand for the Grabowsky Motor Company. But Max and Morris sold their company to General Motors in 1909, which GM used as the beginnings for their Truck division.
General Motors Truck Company produced some of the first commercial trucks ever built and has concentrated on building trucks and larger vehicles since those early days. Originally these production vehicles were branded “GMC Trucks,” but they officially removed the truck portion of the name from vehicle branding in 1998. Since then the pickups, vans, sport utility and other vehicles they produced have simply worn the GMC badge.
Over the years, GMC has produced vehicles for the public, for the government and even for the military. They currently share many similar platforms with Chevrolet, another popular GM brand, and have done so since the 1920s. Chevrolet manufactures a wide range of cars, light trucks and SUVs bearing the familiar Chevy "bowtie" emblem. A familiar crossover example between the two brands would be the GMC Yukon, which is also sold as the Chevrolet Tahoe.
While the GMC acronym might not make perfect since, as it is missing the T for Trucks, it is still a brand with a rich heritage. It is a brand that has withstood the sands of time and continues to play a vital role in the story of automotive manufacturing in the United States.