1. Lighting. A length of cable, similar to a household extension cord, with either Stage Pin or Twist-Lock connectors (if Edison connectors, it's a stinger). Until the obsolescence of the resistance dimmer piano boards, a "cable" (with male stage plug and female stage pin) went from the dimmers to the lighting position, and a "jumper" (stage pins on both ends) ran from two-fers to units. Today the term usually refers to cables 25' or less. Rarely outside of educational theatre does one hear "Get me a 100' jumper for this light". 2. Electronics. User-configurable connection between pins on a printed circuit board to set various modes or voltages. 3. Costumes. Style of skirt or dress with a bib front and integral suspenders/shoulder straps.