ridern.1. One who, or that which, rides.()2. Formerly, an agent who went out with samples of goods to obtain orders; a commercial traveler.()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. (Math.) A problem of more than usual difficulty added to another on an examination paper.()[D. rijder.]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. (Mining) Rock material in a vein of ore, dividing it.()8. (Shipbuilding) An interior rib occasionally fixed in a ship's hold, reaching from the keelson to the beams of the lower deck, to strengthen her frame.(Totten.)9. (Naut.) 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.(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.()