noun
core wire; conductor
Technical term in electrical engineering for the inner conducting wire of a cable, as opposed to the insulation or sheath.
このケーブルは芯線が細いので、大電流には向かない。
This cable has a thin core wire, so it is not suitable for high current.
同軸ケーブルの芯線は中心導体として使われる。
The core wire of a coaxial cable is used as the center conductor.
Compound of 芯 (core) and 線 (wire). The alternate spelling 心線 uses 心 (heart/center) with a similar meaning.