n a traveler who actively rides an animal (as a horse or camel)
n a clause that is appended to a legislative bill
n a traveler who actively rides a vehicle (as a bicycle or motorcycle)
n a traveler riding in a vehicle (a boat or bus or car or plane or train etc) who is not operating it
n. 骑（马、自行车等）的人( rider的名词复数 ); 乘客; 附文; 附加条款