filament

A fine thread or wire.

Such a wire, as can be heated until it glows, in an incandescent light bulb or a thermionic valve.

Lighting was unimaginative for the standard stock with naked tungsten filament bulbs and metal reflectors. However, all compartments had individual reading lights above the seats with attractive glass shades.

A massive, thread-like structure, such as those gaseous ones which extend outward from the surface of the sun, or such as those (much larger) ones which form the boundaries between large voids in the universe.

solar filament

galaxy filament

The stalk of a flower stamen, supporting the anther.

A continuous object, limited in length only by its spool, and not cut to length.