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.
A representative payee, also referred to as a rep payee, is a person, agency, or organization appointed by Social Security to get your SSI and SSDI benefits for you and use those benefits to meet your needs.