Filament (noun)

1. A very thin thread or fiber, especially one of a group that make up a larger structure or object.
2. A thin wire or thread of a material, such as metal or glass, that is used to heat something by passing an electric current through it.
3. The thin thread-like structure that forms the reproductive cells in flowering plants.

Origin:

Late middle english: from latin filamentum, from filare "spin, weave", from filum "thread".

Examples:

1. The spider silk is made of thin filaments.
2. The light bulb filament burns out.
3. The filament in the bulb was made of tungsten.
4. The filament of the fern is used to reproduce.
5. The filament in the muscle is responsible for muscle contraction.