What does the letter S in NASCAR stand for?

The letter S in NASCAR stands for “Stock.” NASCAR is short for National Association for Stock Car Auto Racing, the organization founded in 1948 to sanction and promote stock-car competition.

“Stock car” originally referred to automobiles based on production cars that ordinary buyers could purchase. The sport grew from informal races involving modified road cars, including competition among moonshine runners during Prohibition. Early racers valued cars that were quick, durable, and familiar to mechanics and fans.

The name can cause confusion because NASCAR now uses highly specialized race cars rather than showroom-standard vehicles. Modern Cup Series cars share production-inspired branding and manufacturer identities, but their chassis, engines, aerodynamics, and safety systems are purpose-built for racing.

The other letters are N for National, A for Association, C for Car, and A for Auto; “Racing” supplies the final word. NASCAR has since expanded beyond its original stock-car roots into multiple national series and touring divisions.