1. To bounce up and down and rock from side to side while moving, or to make someone or something move in this way: The truck was jouncing over the ruts in the road and upsetting Paul's stomach.
2. To move or to cause to move repeatedly by bouncing up and down: Marvin's grandfather was enjoying the opportunity to jounce his granddaughter on his knee.
3. Etymology: used from about 1440, of unknown origin; perhaps a blend of jump and bounce.