A person who rides something, most commonly a motorcycle or bike in everyday use, but also usable for horse riding and similar contexts.
Riders must wear a helmet.
乗馬クラブでは、経験豊富なライダーが初心者を指導している。
At the riding club, experienced riders are teaching beginners.
He has competed in numerous races as a rider.
She belongs to a team as a professional rider.
A rider who was going too fast caused an accident.
beam rider
free rider