A rider is someone who rides something, whether it's a horse, bicycle, motorcycle, or even a bus or train. The word describes anyone traveling on or controlling a vehicle or animal. A skilled rider might guide a horse through a jumping course, while a subway rider simply stands holding the rail during their commute.

In legal and government contexts, a rider is something completely different: an additional clause or amendment attached to a bill or contract. Lawmakers sometimes add riders to bills that have nothing to do with the main topic. For instance, a bill about building new schools might have a rider added that changes rules about farming. This practice can be controversial because a rider might pass into law even though it wouldn't have succeeded on its own.

The word also appears in entertainment contracts, where a rider lists specific demands or requirements. A famous musician's rider might request certain foods backstage, particular lighting, or specific equipment.