In the context of cars, it usually refers to vehicles that were originally sold in Japan only. These cars often have unique features, styling, and performance that are not found in other markets.
Here's how it's often used in text:
* "I'm looking for a JDM car, preferably a Honda Civic Type R."
* "That Nissan Skyline GT-R is a classic JDM sports car."
* "The JDM market is known for its high-performance vehicles."
So, if you see JDM in a message about cars, it's referring to a Japanese domestic market vehicle.