What phrase does the 'SS' in Chevrolet Impala SS stand for?

In Chevrolet Impala SS, “SS” stands for Super Sport.

Chevrolet used Super Sport as the name of a performance and appearance package. The badge signaled that an Impala had upgraded sporting equipment rather than identifying a separate automobile brand or a racing-only specification. Depending on the model year, SS equipment could include stronger suspension, special trim, distinctive wheels, improved brakes, and more powerful engines.

The Impala first received the SS package for 1961. That year, the option cost $53.80 and was ordered on 453 Impalas, making the earliest version particularly scarce. Buyers could pair the package with different engines, including Chevrolet’s 348-cubic-inch and 409-cubic-inch V8s.

“Super Sport” is sometimes confused with “Super Stock,” especially because both phrases appeared in American performance-car culture. Chevrolet’s SS designation, however, consistently means Super Sport. The initials later appeared on other Chevrolet models, including the Chevelle, Camaro, Nova, El Camino, Monte Carlo, and various trucks.