What is Coaxial Cable?

Legal Definition
Coaxial cable, or coax (pronounced /ˈk.æks/), is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. Many coaxial cables also have an insulating outer sheath or jacket. The term coaxial comes from the inner conductor and the outer shield sharing a geometric axis. Coaxial cable was invented by English engineer and mathematician Oliver Heaviside, who patented the design in 1880. Coaxial cable differs from other shielded cable used for carrying lower-frequency signals, in that the dimensions of the cable are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a transmission line.
-- Wikipedia
Legal Definition
Heavy-duty, high speed data transmission cable used in computer networks, and cable TV. It is a copper core encased in plastic surrounded by a braided copper shield, covered entirely with plastic insulation. Coax is used for both base-band and broadband communications via a largely interference-free medium.