Coaxial

adj. having a common axis

In geometry, coaxial means that two or more forms share a common axis; it is the three-dimensional linear analog of "concentric".Coaxial cable, as a common example, has a wire conductor in the center (D) a circumferential outer conductor (B) and an insulating medium called the dielectric (C) separating these two conductors. The outer conductor is usually sheathed in a protective PVC outer jacket (A). The dimension and material of the conductors and insulation determine the cables characteristic impedance and attenuation at various frequencies.
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Adjective
1. having a common axis
(synonym) coaxal
(similar) concentric, concentrical, homocentric

adj. coaxial

adj. coaxial, having a common axis