Rider

Part of speech: noun (n.)

1. One who, or that which, rides.

2. Formerly, an agent who went out with samples of goods to obtain orders; a commercial traveler. [Eng.]

3. One who breaks or manages a horse. Shak.

4. An addition or amendment to a manuscript or other document, which is attached on a separate piece of paper; in legislative practice, an additional clause annexed to a bill while in course of passage; something extra or burdensome that is imposed. After the third reading, a foolish man stood up to propose a rider. Macaulay. This [question] was a rider which Mab found difficult to answer. A. S. Hardy.

5. A problem of more than usual difficulty added to another on an examination paper.

6. A Dutch gold coin having the figure of a man on horseback stamped upon it. His moldy money ! half a dozen riders. J. Fletcher.

7. Rock material in a vein of ore, dividing it.

8. An interior rib occasionally fixed in a ship's hold, reaching from the keelson to the beame of the lower deck, to strengthen her frame. Totten.

9. The second tier of casks in a vessel's hold.

10. A small forked weight which straddles the beam of a balance, along which it can be moved in the manner of the weight on a steelyard.

11. A robber. [Obs. or Prov. Eng.] Drummond. Rider's bone (Med.), a bony deposit in the muscles of the upper and inner part of the thigh, due to the pressure and irritation caused by the saddle in riding.