noun
wire rod; wire
Refers to wire as a material or product, especially in industrial contexts such as steel wire rod used for drawing or manufacturing.
この工場では線材を加工して針金を作っている。
This factory processes wire rod to make wire.
針金 is a common word for wire as a thin metal thread, while 線材 is a technical term for wire rod as an industrial material.
Compound of 線 (line, wire) and 材 (material, lumber). The exact historical derivation is uncertain, but the word is a straightforward technical term.