A set of definitions exists in the Senate ESEA bill written and voted out of the HELP Committee (Health, Education, Labor and Pensions).
Reps and sets are terms used by exercise professionals, athletes and individuals in the gym. They provide structure and organization to your workout. If you work with a personal trainer or physical therapist, she will prescribe an exercise based on a specific number of sets and reps.
Definition of rep. : the dosage of an ionizing radiation that will develop the same amount of energy upon absorption in human tissue as one roentgen of X-ray or gamma-ray exposure.