Wikipedia
Kammback
A Kammback is a car body style that derives from the research of the German aerodynamicist Wunibald Kamm in the 1930s. The design calls for a body with smooth contours that continues to a tail that is abruptly cut off. This shape reduces the drag of the vehicle.
"Kammback" is an American term. In Europe the design is generally known as a Kamm tail or K-tail.