0 a physical exercise in which you stand with your feet together and arms down, jump up and spread your arms and legs far apart and land, then jump and bring your feet together and arms down again:
1 a small toy in the shape of a person that can be made to jump or dance with strings or a sliding stick:
They did a lot of push-ups, sit-ups, jumping jacks, and running drills in their PE classes.
Children often deem jumping jacks and chin-ups boring or goofy.
James did a little dance, then, in a fit of enthusiasm, performed jumping jacks.
The jumping jack toy became known as Hampelmann in German-speaking countries.
We are the jumping jacks. They pull the strings and we dance.