What is a compound word for car?

There isn't a single, universally accepted compound word *specifically* meaning "car". The term "car" itself is already quite concise. However, depending on the context, you might use compound words like:

* Motorcar: This is a more formal and slightly older term for a car.

* Railcar: This refers to a car that runs on rails (a train car).

* Sports car: This describes a type of car.

The best compound word to use would depend heavily on the specific meaning you're trying to convey.