"rider" in the noun sense
a traveler who actively rides an animal (as a horse or camel)
a clause that is appended to a legislative bill
a traveler who actively rides a vehicle (as a bicycle or motorcycle)
4. passenger, rider
a traveler riding in a vehicle (a boat or bus or car or plane or train etc) who is not operating it
Source: WordNet® (An amazing lexical database of English)
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