Source : Webster's Revised Unabridged Dictionary (1913)

Dropper \Drop"per\, n.
   1. One who, or that which, drops. Specif.: (Fishing) A fly
      that drops from the leaden above the bob or end fly.

   2. A dropping tube.

   3. (Mining) A branch vein which drops off from, or leaves,
      the main lode.

   4. (Zo["o]l.) A dog which suddenly drops upon the ground when
      it sights game, -- formerly a common, and still an
      occasional, habit of the setter.

Source : WordNet®

dropper
     n : pipet consisting of a small tube with a vacuum bulb at one
         end for drawing liquid in and releasing it a drop at a
         time [syn: {eye dropper}]