Muscle car is a term used to refer to a variety of high performance automobiles. The term principally refers to American, Australian and to a lesser extent South African models. It generally describes a 2-door rear wheel drive mid-size car with a large, powerful V8 engine, and at an affordable price. Although opinions vary, it is generally accepted that classic muscle cars were produced in the late 1960s and early 1970s."Muscle Car Definition" Muscle Car Club Muscle, undated, retrieved on 2008-06-16. Muscle cars were built for street use and in some cases racing. They are distinct from sports cars and also from GTs, which are two-seat or 2+2 cars intended for high-speed touring/road racing. These are not generally considered muscle cars owing to their small size, relatively high cost and specialty nature. (The two-seater AMC AMX may or may not be an exception: one source queries whether it qualifies as a true muscle car or pony car, but also lists it among vehicles that fit the general interpretation of both categories. AMC was "never shy" about describing the car as "a genuine sports car" as it was relatively inexpensive).

For a definition from the muscle car era, Peter Henshaw's 2004 book Muscle Cars refers the reader to an extract from Road Test magazine's June 1967 issue: "Just what is a Muscle Car? Exactly what the name implies. It is a product of the American car industry adhering to the hot rodder's philosophy of taking a small car and putting a BIG engine in it 1 The Muscle Car is Charles Atlas kicking sand in the face of the weakling." Henshaw adds that the muscle car was designed for straight-line speed, and did not have the "sophisticated chassis", "engineering integrity" or "lithe appearance" of European high-performance carsHenshaw, Peter (2004): Muscle Cars, Thunder Bay Press. ISBN 1-59223-303-1

Opinions vary as to whether high-performance full-size cars, compacts, and pony cars qualify as muscle cars.

Classic muscle cars are also defined by age and country of origin. The term "muscle car" did not enter common usage until after production of the vehicles had essentially ended, and American print media of the era commonly referred to them as "supercars".

Early muscle

Musclecars magazine wrote: "2he idea of putting a full-size V8 under the hood of an intermediate body and making it run like Jesse Owens in Berlin belongs to none other than Oldsmobile... 3 all-new ohv V8...Rocket engine quickly found its way into the lighter 76 series body, and in February 1949, the new 88 series was born."Musclecars magazine, 1994.