1. One that rides, especially one who rides horses.

2. An unrelated provision added to a legislative bill as a means of trying to get the provision adopted along with the bill or to hamper the passage of the bill.

3. An amendment or addition annexed to a document, of which it is considered to be a part. Also called allonge.

4. Something, such as the top rail of a fence, that rests on or is supported by something else.