Japanese Domestic Market. Refers to vehicles, parts, or styling sold or used in Japan, often imported elsewhere through grey-market channels.
JDM stands for Japanese Domestic Market. Strictly, the term refers to vehicles or parts sold by manufacturers specifically for the Japanese market. Many JDM cars were never officially exported, which is why importing them (typically once they reach 25 years of age in the United States) has become a major hobby.
In casual use, JDM has expanded to mean any styling or modification influenced by Japanese tuner culture. A Honda Civic with a stance setup, JDM-spec headlights, and Japan-only trim parts would be called JDM by most enthusiasts even if the car is a North American model. The strict definition would limit JDM to actual Japan-market vehicles.
Common JDM imports in the United States include the Skyline GT-R (R32, R33, R34), Toyota Chaser, Mazda RX-7 Spirit R, Honda Beat, Nissan Silvia S15, and Mitsubishi Lancer Evolution variants that were never sold in North America. The Right Hand Drive (RHD) configuration is a quick visual indicator of an authentic JDM import.