The term "Jumping Jacks" refers to a type of exercise that involves jumping while keeping the body in a stationary position. It is also known as "Jacks" or "Kangaroo Jumps." The movement typically starts with the feet together, followed by jumping out and spreading the legs wide apart, then bringing them back together again to make a small hop. This exercise can be done while standing still or in motion, making it an excellent way to get your heart rate up and improve cardiovascular endurance.