Car model names generally stand for the code names used in the early stages of development. This is the case with the 2015 Dodge Challenger Hellcat.
Jaguar made the XJ6 car model. XG350 is a Hyundai car model.
Cervo is a car model of Suzuki. Swift is a car model made by Suzuki.
Ford used letters as model names instead of words in the beginning. That car was called the Model T and that was it's name. Ford started using names as models later on in the 1930s.
If you are talking about a Cadillac, It is a model or version of that car.
One movie is "The Model T, Car of The Century"
Cobalt LS does not stand for anything specific, but the LS letters are there to signify the different features of the car model. LS usually means it is the model that comes with the least amount of features.
As both Ferrari and Pagani are BRAND names and not MODELS of car, that would depend on WHICH Ferrari, and Pagani, model of car.
If the car is an S6 instead of an A6 then it is the sport model of that car. This means the car has a more powerful engine and all the equipment to go along with that power.
Below website is the most comprehensive listing I could find ( in the links).
Nomad means Wanderer. On the Chevrolet it was a model designation for the Chevrolet Nomad station wagon.
He started out using an alphabetical system. But after he had sold over 15 million Model Ts he then named his next car the Model A instead of Model U. He had already used on A on a previous model but he said the new car was so different he wanted to start over with the model names.
Model designation, Model "A", Model "T", Model "B".