A coupe or coupé is a passenger car with a sloping or truncated rear roofline and typically with two doors.
Audi TT coupé
1955 Cadillac Coupe de Ville
Example of a coupe carriage
Volvo C70, an example of a convertible coupe
A fastback is an automotive styling feature, defined by the rear of the car having a single slope from the roof to the tail.
1935 Stout Scarab
1949 Cadillac Series 62 rear