Jacket - The outer covering on a cable or wire that may provide electrical insulation and/or resistance to abrasion, chemicals, and moisture.
Jams - Tunes, rocks, hits, sounds good, etc.
Japanese Industrial Standards Committee (JISC or JIS) - A Japanese agency that establishes and maintains standards for equipment and components.
Jewel Case - The hard plastic case that contains a compact disc.
JISC - Often called JIS, refer to Japanese Industrial Standards Committee
Joule - A derived unit of energy or work, named after English physicist James Prescott Joule. I is equal to the energy expanded (or work done) in applying a force of one Newton through a distance of one meter (1 Newton Meter or Nm), or in passing an electric current in one ampere through a resistance of one Ohm for one second.
Jump - To provide a temporary circuit around a component or other circuit.
Junk - Discarded or useless; of no value.