The Acura MDX is a three-row mid-size luxury crossover SUV produced by the Japanese automaker Honda under its Acura luxury nameplate since 2000. The alphanumeric moniker stands for "Multi-Dimensional luxury". It has ranked as the second-best selling mid-size luxury SUV after the Lexus RX.The MDX was the first crossover SUV to have third-row seating, and shares its platform with the Honda Pilot. The Pilot is available with a seven or eight person seating configuration, while the MDX exclusively seats seven, with two seating positions in the third row. The MDX was introduced on October 5, 2000 as a 2001 model, replacing the slow-selling U.S.-only body-on-frame SLX, based on the Isuzu Trooper. In Japan, it filled a gap when the Honda Horizon (also based on the Trooper) was discontinued in 1999. In 2003, the vehicle went on sale in Japan and Australia as the Honda MDX; sales with Honda badges ended with the introduction of the second generation three years later.