The Collaborative International Dictionary of English v.0.48:

Breeches \Breech"es\ (br[i^]ch"[e^]z), n. pl. [OE. brech, brek,
   AS. br[=e]k, pl. of br[=o]c breech, breeches; akin to Icel.
   br[=o]k breeches, ODan. brog, D. broek, G. bruch; cf. L.
   bracae, braccae, which is of Celtic origin. Cf. Brail.]
   1. A garment worn by men, covering the hips and thighs;
      smallclothes.
      [1913 Webster]

            His jacket was red, and his breeches were blue.
                                                  --Coleridge.
      [1913 Webster]

   2. Trousers; pantaloons. [Colloq.]
      [1913 Webster]

   Breeches buoy, in the life-saving service, a pair of canvas
      breeches depending from an annular or beltlike life buoy
      which is usually of cork. This contrivance, inclosing the
      person to be rescued, is hung by short ropes from a block
      which runs upon the hawser stretched from the ship to the
      shore, and is drawn to land by hauling lines.

   Breeches pipe, a forked pipe forming two branches united at
      one end.

   Knee breeches, breeches coming to the knee, and buckled or
      fastened there; smallclothes.

   To wear the breeches, to usurp the authority of the
      husband; -- said of a wife. [Colloq.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Buoy \Buoy\ (bwoi or boi; 277), n. [D. boei buoy, fetter, fr.
   OF. boie, buie, chain, fetter, F. bou['e]e a buoy, from L.
   boia. "Boiae genus vinculorum tam ferreae quam ligneae."
   --Festus. So called because chained to its place.] (Naut.)
   A float; esp. a floating object moored to the bottom, to mark
   a channel or to point out the position of something beneath
   the water, as an anchor, shoal, rock, etc.
   [1913 Webster]

   Anchor buoy, a buoy attached to, or marking the position
      of, an anchor.

   Bell buoy, a large buoy on which a bell is mounted, to be
      rung by the motion of the waves.

   Breeches buoy. See under Breeches.

   Cable buoy, an empty cask employed to buoy up the cable in
      rocky anchorage.

   Can buoy, a hollow buoy made of sheet or boiler iron,
      usually conical or pear-shaped.

   Life buoy, a float intended to support persons who have
      fallen into the water, until a boat can be dispatched to
      save them.

   Nut buoy or Nun buoy, a buoy large in the middle, and
      tapering nearly to a point at each end.

   To stream the buoy, to let the anchor buoy fall by the
      ship's side into the water, before letting go the anchor.


   Whistling buoy, a buoy fitted with a whistle that is blown
      by the action of the waves.
      [1913 Webster]

WordNet (r) 3.0 (2006):

breeches buoy
    n 1: a life buoy in the form of a ring with short breeches for
         support; used to transfer people from a ship