BMX
/ˌbiːemˈeks/noun
as modifier
- denoting or relating to bicycles of a robust design suitable for cross-country racing适用于越野赛的自行车：
a BMX bike
越野自行车
count noun he'd seen Barry on his BMX.他看见巴里骑着越野自行车。
词源
1970s: from the initial letters of bicycle motocross, with X standing for cross.