noun

• A mounted person.
• (now archaic or historical) A knight, or other mounted warrior.
• An old Dutch gold coin with the figure of a man on horseback stamped upon it.
• (generally) Someone who rides a horse or (later) a bicycle, motorcycle etc.
• (now historical or archaic) A mounted robber; a bandit, especially in the Scottish borders.
• (obsolete) Someone who breaks in or manages a horse; a riding master.
• (now rare, historical) An agent who goes out with samples of goods to obtain orders; a commercial traveller or travelling salesman.
• (now chiefly US) Someone riding in a vehicle; a passenger on public transport.
• An addition, supplement.
• (politics) A supplementary clause added to a document after drafting, especially to a bill under the consideration of a legislature.
• An amendment or addition to an entertainer's performance contract, often covering a performer's equipment or food, drinks, and general comfort requirements.
• An additional matter or question arising in corollary; a qualification.
• A supplementary question, now especially in mathematics.
• Technical senses.
• (shipbuilding) An interior rib occasionally fixed in a ship's hold, reaching from the keelson to the beams of the lower deck, to strengthen the frame.
• (mining, now rare) Rock material in a vein of ore, dividing it.
• (nautical, in the plural) The second tier of casks in a vessel's hold.
• A small, sliding piece of thin metal on a balance, used to determine small weights.
• (cartomancy) The first Lenormand card, also known as either the horseman or the cavalier.
• (chess) A piece, such as the rook or bishop, which moves any distance in one direction, as long as no other piece is in the way.
• A surname originating as an occupation. More often spelled Ryder.