fishing line

This term refers specifically to the specialized filament used in angling. While "line" is a general term for any string, "fishing line" implies a specific set of material properties, such as tensile strength, diameter, and invisibility underwater, designed to withstand the struggle of a fish.

In a technical context, the term encompasses various materials including monofilament, fluorocarbon, and braided lines. It is almost always used as a concrete noun referring to the physical equipment rather than a metaphorical connection.