If the back window lifts up to get into the trunk it's a hatch, there are probably more specific traits but that's the jist of it. A coupe is a two seater car with a separate trunk and less than 30 SqIn of rear footspace. You may also hear coupe refered to as "notchbacks" when refering to mustangs. I hope you enjoy the fascinating world of automobiles and can ignore those who should be.