fil·a·ment | \ ˈfi-lə-mənt \

Definition of filament 

: a single thread or a thin flexible threadlike object, process, or appendage (see appendage sense 2): such as

a : a tenuous (see tenuous sense 2) conductor (as of carbon or metal) made incandescent by the passage of an electric current specifically : a cathode (see cathode sense 2) in the form of a metal wire in an electron tube

b(1) : a thin and fine elongated constituent part of a gill (see gill entry 2 sense 1)

(2) : an elongated thin series of cells attached one to another or a very long thin cylindrical single cell (as of some algae, fungi, or bacteria)

c : the anther-bearing stalk of a stamen — see flower illustration

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Other words from filament

filamentary \ˌfi-lə-ˈmen-t(ə-)rē \ adjective
filamentous \ˌfi-lə-ˈmen-təs \ adjective

Synonyms for filament


bristle, fiber, hair, thread

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Examples of filament in a Sentence

algae covered with tiny filaments the cable was made up of fine filaments twisted together

Recent Examples on the Web

The fine, hairlike root tips of trees join together with microscopic fungal filaments to form the basic links of the network, which appears to operate as a symbiotic relationship between trees and fungi, or perhaps an economic exchange. Diàna Markosian, Smithsonian, "Do Trees Talk to Each Other?," 22 Feb. 2018 Those protrusions are topped by a ring of string-like filaments. David Grossman, Popular Mechanics, "New Tardigrade Species Found in Parking Lot," 28 Feb. 2018 However, the simulations show that gas pours into a galaxy in cold streams that flow along the dark matter filaments connecting its halo to the cosmic web, Dekel says. Adrian Cho, Science | AAAS, "Galaxy simulations are at last matching reality—and producing surprising insights into cosmic evolution," 30 May 2018 Microfibers are individual plastic filaments that are woven together to make fabrics like polyester, nylon, acrylic, and so on. National Geographic, "Plastics Explained, From A to Z," 16 May 2018 In the video, the anglerfish’s filaments and fin-rays also appeared to be glowing. Brigit Katz, Smithsonian, "Elusive Deep-Sea Anglerfish Seen Mating for the First Time," 26 Mar. 2018 The factory in question produces wound-filament airframes and nozzles for engines used in solid-fuel missiles, particularly the Pukguksong series of rockets, the report said. Time, "Satellite Images Show North Korea Is Expanding a Missile-Manufacturing Plant, a Report Finds," 2 July 2018 Many property owners have crisscrossed filament over their roofs, for example, or owl statues meant to scare the birds off. Billy Baker,, "The gull next door: Some Gloucester residents can’t stand all the seabirds," 19 June 2018 Andrew Penketh Andrew Penketh Not all filament bulbs are created equal, though. Liz Stinson, Curbed, "Plumen makes a pair of not-so-tired Edison bulbs," 20 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'filament.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of filament

1594, in the meaning defined above

History and Etymology for filament

Middle French, from Medieval Latin filamentum, from Late Latin filare to spin — more at file

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Statistics for filament

Last Updated

17 Aug 2018

Look-up Popularity

Time Traveler for filament

The first known use of filament was in 1594

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English Language Learners Definition of filament

: a thin thread or hair

: a thin wire in a light bulb that glows when electricity passes through it


fil·a·ment | \ ˈfi-lə-mənt \

Kids Definition of filament

1 : a fine thread a filament of silk

2 : a fine wire (as in a light bulb) that is made to glow by the passage of an electric current

3 : the stalk of a plant stamen that bears the anther


fil·a·ment | \ ˈfil-ə-mənt \

Medical Definition of filament 

: a single thread or a thin flexible threadlike object, process, or appendage especially : an elongated thin series of cells attached one to another or a very long thin cylindrical single cell (as of some algae, fungi, or bacteria)

Other words from filament

filamentous \ˌfil-ə-ˈment-əs \ adjective

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More from Merriam-Webster on filament

Thesaurus: All synonyms and antonyms for filament

Spanish Central: Translation of filament

Nglish: Translation of filament for Spanish Speakers

Britannica English: Translation of filament for Arabic Speakers

Comments on filament

What made you want to look up filament? Please tell us where you read or heard it (including the quote, if possible).


an open space surrounded by woods

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