Possible Definitions:
1. Dropper (n.) One who, or that which, drops. Specif.: (Fishing) A fly that drops from the leaden above the bob or end fly.
2. Dropper (n.) A dropping tube.
3. Dropper (n.) A branch vein which drops off from, or leaves, the main lode.
4. Dropper (n.) A dog which suddenly drops upon the ground when it sights game, -- formerly a common, and still an occasional, habit of the setter.