filament

In astronomy, dark, winding feature occasionally seen on images of the Sun in hydrogen light. Filaments are clouds of relatively cool gas suspended above the Sun by magnetic fields and seen in silhouette against the hotter photosphere below. During total eclipses they can be seen as bright features against the sky at the edge of the Sun, where they are known as prominences.

filament

Single long fibre used to produce yarn for different types of fabric. Synthetic fibre is initially produced as single filaments, made when liquid polymer is forced through fine holes in a device called a spinneret. The resulting filaments are hardened, drawn, and twisted to produce a yarn, or cut to form staple (shorter) fibres. Silk is the only naturally occurring single filament fibre.

A continuous filament of up to 3 km/2 mi can be unwound from the cocoon of a silkworm.