Skid \Skid\ (sk[i^]d), n. [Icel. sk[imac][eth] a billet of wood.
   See Shide.] [Written also skeed.]
   1. A shoe or clog, as of iron, attached to a chain, and
      placed under the wheel of a wagon to prevent its turning
      when descending a steep hill; a drag; a skidpan; also, by
      extension, a hook attached to a chain, and used for the
      same purpose.
      [1913 Webster]

   2. A piece of timber used as a support, or to receive
      pressure. Specifically:
      (a) pl. (Naut.) Large fenders hung over a vessel's side to
          protect it in handling a cargo. --Totten.
      (b) One of a pair of timbers or bars, usually arranged so
          as to form an inclined plane, as form a wagon to a
          door, along which anything is moved by sliding or
          rolling.
      (c) One of a pair of horizontal rails or timbers for
          supporting anything, as a boat, a barrel, etc.
          [1913 Webster]

   3. (Aeronautics) A runner (one or two) under some flying
      machines, used for landing.
      [Webster 1913 Suppl.]

   4. A low movable platform for supporting heavy items to be
      transported, typically of two layers, and having a space
      between the layers into which the fork of a fork lift can
      be inserted; it is used to conveniently transport heavy
      objects by means of a fork lift; -- a skid without wheels
      is the same as a pallet.
      [PJC]

   5. pl. Declining fortunes; a movement toward defeat or
      downfall; -- used mostly in the phrase

   on the skids and

   hit the skids.
      [PJC]

   6. [From the v.] Act of skidding; -- called also side slip.
      [Webster 1913 Suppl.]