Bikers are people who ride around on motorbikes, usually in groups.
N-COUNT
騎自行車的人；自行車手
People who ride bicycles are called bikers .
英英詞典釋義
Noun
1. originally a British youth subculture that evolved out of the teddy boys in the 1960s; wore black leather jackets and jeans and boots; had greased hair and rode motorcycles and listened to rock'n'roll; were largely unskilled manual laborers