The Collaborative International Dictionary of English v.0.48:

Paddle \Pad"dle\, n. [See Paddle, v. i.]
   1. An implement with a broad blade, which is used without a
      fixed fulcrum in propelling and steering canoes and boats.
      [1913 Webster]

   2. The broad part of a paddle, with which the stroke is made;
      hence, any short, broad blade, resembling that of a
      paddle, such as that used in table tennis.
      [1913 Webster]

            Thou shalt have a paddle upon thy weapon. --Deut.
                                                  xxiii. 13.
      [1913 Webster]

   3. One of the broad boards, or floats, at the circumference
      of a water wheel, or paddle wheel.
      [1913 Webster]

   4. A small gate in sluices or lock gates to admit or let off
      water; -- also called clough.
      [1913 Webster]

   5. (Zool.) A paddle-shaped foot, as of the sea turtle.
      [1913 Webster]

   6. A paddle-shaped implement for stirring or mixing.
      [1913 Webster]

   7. [In this sense prob. for older spaddle, a dim. of spade.]
      See Paddle staff (b), below. [Prov. Eng.]
      [1913 Webster]

   Paddle beam (Shipbuilding), one of two large timbers
      supporting the spring beam and paddle box of a steam
      vessel.

   Paddle board. See Paddle, n., 3.

   Paddle shaft, the revolving shaft which carries the paddle
      wheel of a steam vessel.

   Paddle staff.
      (a) A staff tipped with a broad blade, used by mole
          catchers. [Prov. Eng.]
      (b) A long-handled spade used to clean a plowshare; --
          called also plow staff. [Prov. Eng.]

   Paddle steamer, a steam vessel propelled by paddle wheels,
      in distinction from a screw propeller.

   Paddle wheel, the propelling wheel of a steam vessel,
      having paddles (or floats) on its circumference, and
      revolving in a vertical plane parallel to the vessel's
      length.
      [1913 Webster] paddlebox

WordNet (r) 3.0 (2006):

paddle wheel
    n 1: a large wheel fitted with paddles and driven by an engine
         in order to propel a boat [syn: paddlewheel, paddle
         wheel]