Coax (Coaxial Cable)

A round cable where one of the conductors is a thin wire running down the middle and the other conductor (usually grounded) is a cylindrical shell or braid  that surrounds the first conductor. Some "two conductor plus ground" cables have two thin wires running down the middle. Other cables have one wire in the middle surrounded by two concentric shells. Coax cable is often used to connect video components. The insulating material that keeps the center conductor centered determines the quality of the cable and/or the kinds of video signals that the cable can carry without degradation. Some people reserve the words "coax cable" to refer to the round 75 Ohm cable that carries TV signals from an antenna or cable TV system.