What is "baby jumper"

jumper \jump"er\ (j[u^]mp"[~e]r), 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.

n. A hoop suspended by an elastic strap, in which a young child may be held secure while amusing itself by jumping on the floor.