What does "bmx" mean?

Bicycle motocross, a form of cycling on BMX bikes, originating in California in the 1970s.

What is a synonym for "bmx"?

Common synonyms include: bicycle motocross, bike motocross.

Pronounced //biː ɛm ˈɛks//.

//biː ɛm ˈɛks// noun, verb

noun, verb ·Rare ·Advanced level

Noun

1
Bicycle motocross, a form of cycling on BMX bikes, originating in California in the 1970s. uncountable
"“When I was in Switzerland going through rehab, literally, I was like, ‘What’s the point? I’m going through so much pain right now and BMX has given me a lot of grief,’” said Sakakibara."
2
A BMX bike. countable
"In the end, why not be happy with both, with the BMXes and the pentathlons, with the swans of synchro and the Quasimodos of wrestling? Sweet."

Verb

1
To ride a BMX bike. intransitive
"I BMXed from 1978 (my first race) till not too long ago. Although I don't see too many freestylers in the net, I get in touch with quite a few ex-BMXers like myself on rec.bicycles.off-road (I'm cross-posting to it)."