filament

American  

[fil-uh-muhnt] / ˈfɪl ə mənt /

noun

1. a very fine thread or threadlike structure; a fiber or fibril.

   filaments of gold.

2. a single fibril of natural or synthetic textile fiber, of indefinite length, sometimes several miles long.

3. a long slender cell or series of attached cells, as in some algae and fungi.

4. Botany. the stalklike portion of a stamen, supporting the anther.

5. Ornithology. the barb of a down feather.

6. (in a light bulb or other incandescent lamp) the threadlike conductor, often of tungsten, in the bulb that is heated to incandescence by the passage of current.

7. Electronics. the heating element (sometimes also acting as a cathode) of a vacuum tube, resembling the filament in an incandescent bulb.

8. Astronomy. a solar prominence, as viewed within the sun's limb.

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filament British  

/ -trɪ, ˌfɪləˈmɛntərɪ, ˈfɪləmənt /

noun

1. the thin wire, usually tungsten, inside a light bulb that emits light when heated to incandescence by an electric current

2. electronics a high-resistance wire or ribbon, forming the cathode in some valves

3. a single strand of a natural or synthetic fibre; fibril

4. botany

   1. the stalk of a stamen

   2. any of the long slender chains of cells into which some algae and fungi are divided

5. ornithol the barb of a down feather

6. anatomy any slender structure or part, such as the tail of a spermatozoon; filum

7. astronomy

   1. a long structure of relatively cool material in the solar corona

   2. a long large-scale cluster of galaxies

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filament Scientific  

/ fĭl′ə-mənt /

1. A fine or slender thread, wire, or fiber.

2. The part of a stamen that supports the anther of a flower; the stalk of a stamen.

3. See more at flower

4. 1. A fine wire that gives off radiation when an electric current is passed through it, usually to provide light, as in an incandescent bulb, or to provide heat, as in a vacuum tube.

   2. A wire that acts as the cathode in some electron tubes when it is heated with an electric current.

5. Any of the dark, sinuous lines visible through certain filters on the disk of the Sun. Filaments are solar prominences that are viewed against the solar surface rather than being silhouetted along the outer edges of the disk.

6. See more at prominence

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Other Word Forms

• filamentary adjective
• filamented adjective

Etymology

Origin of filament

1585–95; < New Latin fīlāmentum, equivalent to Late Latin fīlā ( re ) to wind thread, spin ( file ¹ ) + Latin -mentum -ment

Example Sentences

As people have begun to print more and more whistles, they’ve also tacked on their own unique touches to the designs: messages of protest, information about immigrants’ rights hotlines, special filament colors.

From Slate • Jan. 31, 2026

"Baird would have used ordinary filament lamps, no micro controllers, very basic photodiodes, nowhere near what we've got now," Toms said.

From BBC • Jan. 26, 2026

Some clear glass halos and discs hang in space, suspended on filament.

From Los Angeles Times • Sep. 17, 2024

After producing a ceiling lamp with a bulbous glass filament that rises from the center to evoke a water drop splashing in a pool, Beacon Custom Lighting followed with its Pond decanter.

From Seattle Times • May 28, 2024

Retrace the filament and you go back to the cocoon’s beginning in a tiny knot, a first tentative loop.

From "Middlesex: A Novel" by Jeffrey Eugenides

Related Words

• fiber
• thread