A conducting wire or thread with a high melting point, forming part of an electric bulb or vacuum tube and heated or made incandescent by an electric current.

The filament in the light bulb burned out, causing the room to go dark.

A long chain of proteins, such as actin or myosin, that is part of the cytoskeleton in cells.

The muscle contraction is facilitated by the sliding of actin and myosin filaments.

In botany, the slender stalk of a stamen that supports the anther.

Under the microscope, the filament of the flower's stamen appeared almost translucent.

filamentverb

(transitive) To furnish or cover with filaments; to form into very fine threads.

The 3-D printer filaments the plastic, producing intricate lattices.

(intransitive) To separate into filaments or become filamentous.

When exposed to the solvent, the polymer began to filament and lose its shape.