Source : Webster's Revised Unabridged Dictionary (1913)

Jumper \Jump"er\, n.
   1. One who, or that which, jumps.

   2. A long drilling tool used by masons and quarrymen.

   3. A rude kind of sleigh; -- usually, a simple box on runners
      which are in one piece with the poles that form the
      thills. [U.S.] --J. F. Cooper.

   4. (Zo["o]l.) The larva of the cheese fly. See {Cheese fly},
      under {Cheese}.

   5. (Eccl.) A name applied in the 18th century to certain
      Calvinistic Methodists in Wales whose worship was
      characterized by violent convulsions.

   6. (Horology) spring to impel the star wheel, also a pawl to
      lock fast a wheel, in a repeating timepiece.

   {Baby jumper}. See in the Vocabulary.

   {Bounty jumper}. See under {Bounty}.

Baby jumper \Ba"by jump`er\
   A hoop suspended by an elastic strap, in which a young child
   may be held secure while amusing itself by jumping on the
   floor.