Definition of filament in US English:



  • 1A slender threadlike object or fiber, especially one found in animal or plant structures.

    ‘each myosin filament is usually surrounded by 12 actin filaments’
    • ‘They are twisted masses of tiny filaments or fibers inside nerve cells.’
    • ‘Place it indoors, in a quiet room, and the smoke becomes a cloud of wispy filaments, swirling gently until they all blend into a screen of gray.’
    • ‘For example, all three contract when a rise in calcium inside the muscle cell allows interaction between actin and myosin filaments.’
    • ‘He had division of the terminal filament for a tethered spinal cord, which was thought to be the cause of his symptoms.’
    • ‘They use it to convert energy into movement, exerted against polar actin filaments.’
    • ‘We determined the dissociation constants of our mutants for skeletal muscle actin using capped filaments.’
    • ‘Her fur was standing on end, like filaments of wire.’
    • ‘Tinted prints of Andy Warhol's inflated ‘silver clouds’ dangled on filaments in the first and second galleries.’
    • ‘Her only connection to the world a tenuous filament of wires, tubes and intravenous needles.’
    • ‘On a transparent blue expanse, a swaddled figure lies in a passive curve, suspended in a heavenly hammock of spidery filaments, surrendered to the life of the mind.’
    fibre, thread, strand, tendril
    View synonyms
    1. 1.1Botany The slender part of a stamen that supports the anther.
      • ‘The style is enclosed in a tube formed by the five fused anthers and filaments.’
      • ‘In these flowers, the anthers are attached to the petals by short filaments half way down the corolla tube.’
      • ‘At the balloon stage of flowering, petals were peeled away and the swollen anthers were removed from the filaments by rubbing the open flower on wire mesh.’
      • ‘Short and long stamens were measured from the base of the filament to the tip of the anthers.’
      • ‘Smearing of pollen is facilitated by the fanning out of anthers borne at the ends of the filaments.’
    2. 1.2Astronomy A slender, elongated body of luminous gas or other material in the sun’s atmosphere, a nebula, or interstellar space.
      • ‘Picking a fax out of the machine, he reviewed the hand sketches of sunspots, coronal holes, filaments, and prominences of the Sun as drawn by observers at Holloman Air Force Base in New Mexico.’
  • 2A 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.

    • ‘An incandescent light bulb contains a thin wire filament (usually tungsten) that glows hot when an electric current is run through it.’
    • ‘In an incandescent bulb, the filament is made of a thin piece of tungsten metal, coiled to fit inside the bulb; if it were stretched out, it would measure about 6 feet long!’
    • ‘Unlike an incandescent bulb, no filament is needed.’
    • ‘By incorporating nanowires as filaments in bigger superconducting wires, for example, more current could be carried without being destroyed by a magnetic field.’
    • ‘In one experiment, the researchers formed the yarn into a lightbulb filament and found that its strength and conductivity increased after it heated up.’
    • ‘The inert gas prevents the wire filament inside the bulb from reacting chemically with oxygen and burning out quickly.’
    • ‘The new lamp not only has the size and shape of a conventional filament bulb but also comes with a standard screw base and can therefore be fitted in any lamp or light socket.’
    • ‘The filaments in the lightbulbs we'd started manufacturing kept burning up.’
    • ‘The most important factors determining the heating of a filament to incandescence are thermal mass and electrical resistance of the filament.’
    • ‘It was as white and alive as the filament of a light bulb viewed close up.’
    • ‘Lewis Latimer, the son of runaway slaves, became an electrical engineer and invented an inexpensive process for making light bulb filaments.’
    • ‘It glimmers at barely 1800 degrees Fahrenheit, which is cooler than a light bulb filament.’
    • ‘But unlike ordinary incandescent bulbs, they don't have a filament that will burn out, and they don't get especially hot.’
    • ‘The tungsten filament of an incandescent light is an example of a wire under extreme conditions.’
    • ‘An incandescent black light bulb is similar to a normal household light bulb, but it uses light filters to absorb the light from the heated filament.’
    • ‘A strong, alternating current heats a resistive filament, causing it to emit electrons.’
    • ‘As he watched it burn he noticed how individual strands of the wood glowed white as they burned fiercely, and that convinced him that bamboo might be the best material to use for his light bulb filaments.’
    • ‘Regular incandescent light bulbs produce light by heating a small filament inside the bulb.’
    • ‘It is like comparing a red-hot poker pulled from a fire with the filament in an electric light bulb: there is no doubt concerning which is the brighter.’
    • ‘He used a carbon filament in an oxygen-free bulb.’
    cord, rope, string, cable, wire, thread, twine, strand, ligature
    View synonyms


Late 16th century: from French, or from modern Latin filamentum, from late Latin filare ‘to spin’, from Latin filum ‘thread’.