WordWeb Online

1. A traveller who actively rides an animal (as a horse or camel)
    
2. A clause that is appended to a legislative bill
    
3. A traveller who actively rides a vehicle (as a bicycle or motorcycle)
    
4. A traveller riding in a vehicle (a boat, bus, car, plane or train etc) who is not operating it
   "The taxi driver who felt he didn't get a high enough tip cursed the rider";
   - passenger

Derived forms: riders

Type of: article, clause, traveler [US], traveller [Brit, Cdn]

Part of: bill, legislative act, measure, statute

Encyclopedia: Rider, Steve