What makes a muscle car a muscle car?

Muscle cars are straight line performance based( atleast in the old days) more concentrated on et/mph and tire smoke. It was putting the large/hot motor in a light model car, best power/weight. It started with placing large motors originally reserved for full size models into mid size cars. Handle and braking back in the day to a backseat to hp. The line started to blur with models like the z/28, boss 302, 340 cudas which actually could have been classified as sports cars.