The Acura MDX, or Honda MDX as known in Japan and Australia (only the first generation was imported), is a mid-size three-row luxury crossover SUV produced by the Japanese automaker Honda under its Acura luxury nameplate since 2000. The alphanumeric moniker stands for "Multi-Dimensional luxury". According to Honda, the MDX is the best-selling three-row luxury crossover of all time, with cumulative U.S. sales expected to surpass 700,000 units before the end of 2014. It has ranked as the second-best selling luxury crossover after the Lexus RX, which offers only two rows of seats. The MDX was the first crossover SUV to have third-row seating, and shares a platform with the Honda Pilot. The Pilot seats eight, while the MDX seats seven, with two seating positions in the third row. The MDX was introduced 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 Honda MDX went on sale in Japan and Australia. The MDX has been the most expensive crossover in Acura's lineup, except for the 2009-13 model years when Acura added a crossover to slot above the MDX, called the ZDX.