Wiktionary
pony car
n. (context US automotive English) An affordable, compact, highly styled car with a sporty or performance-oriented image.
Wikipedia
Pony car
Not to be confused with the Hyundai Pony car.
Pony car is an American class of automobile launched and inspired by the Ford Mustang in 1964. The term describes an affordable, compact, highly styled car with a sporty or performance-oriented image.