a traveler who actively rides an animal (as a horse or camel)
"The weary rider guided his tired horse through the dusty canyon at sunset."
a clause that is appended to a legislative bill
"The senator proposed an amendment adding a new rider to the defense budget bill."
a traveler who actively rides a vehicle (as a bicycle or motorcycle)
"The tired rider pedaled hard to catch up with the group before sunset."
A mounted person.
"The rider urged his horse forward to catch up with the others in the race."
A knight, or other mounted warrior.
"The brave rider charged forward on his steed to defend the kingdom."
In plain English: A rider is an extra rule added to a contract that changes how it works for specific situations.
"The horse rider adjusted her helmet before starting down the trail."
A surname, from occupations. More often spelled Ryder.
"The historical records list John Rider as a prominent member of his guild, though most modern descendants spell their family name Ryder."
The word rider comes from the Late Old English term rīdere, which originally meant a person who rides or a knight. It entered Middle English as ryder and has since remained in use with its core meaning intact.