What does BMX stand for in BMX racing?

In BMX racing, BMX stands for Bicycle motocross.

The name reflects the sport’s origins: bicycle racing on dirt tracks was developed in the United States by young riders inspired by motorcycle motocross. BMX racing uses bicycles rather than motorcycles, but it borrowed motocross-style features such as jumps, banked turns, dirt courses and fast mass starts.

Organised BMX emerged in Southern California in the late 1960s and early 1970s. One early race was held at Palms Park in West Los Angeles on 10 July 1969, where children raced modified Schwinn Sting-Ray bicycles. The sport spread quickly, and international governing structures later developed, including UCI-sanctioned competition.

BMX is now used for both racing and freestyle disciplines, which can cause confusion about the name. Racing focuses on speed around a short track, while freestyle emphasises tricks and creativity. BMX racing became an Olympic medal sport at the 2008 Beijing Games. “Bike motocross” is sometimes used informally, but “Bicycle motocross” is the standard expansion expected in this question.