fil·​a·​ment | \ ˈfi-lə-mənt How to pronounce filament (audio) \

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 How to pronounce filamentary (audio) \ adjective
filamentous \ ˌfi-​lə-​ˈmen-​təs How to pronounce filamentous (audio) \ 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

UC Santa Barbara holds several patents for filament-style LED technology. Jordan Valinsky, CNN, "Walmart, Amazon and Ikea sued over Edison light bulbs," 31 July 2019 The air flows through the filaments and leaves a swirling trail of air behind, or what’s called a separated vortex ring. Rachael Lallensack, Smithsonian, "Five Scientific Findings That Could Lead to New Inventions," 13 July 2019 Putting out feelers There is one intriguing clue as to why Elektorornis had such long toes: The amber-entombed foot preserves bits of the surrounding skin and feathers, including strands called scutellate scale filaments. Michael Greshko, National Geographic, "Ancient bird foot found in amber has bizarrely long toes," 11 July 2019 At the mine, Rojas shows us rocks with gold filaments, which must be extracted. Vasco Cotovio, CNN, "A trail of 'bloody gold' leads to Venezuela's government," 20 Aug. 2019 Clusters, filaments and sheets are the dense regions where galaxies are common. NBC News, "Master plan of the universe revealed in new galaxy maps," 11 Aug. 2019 The dangling Edison bulbs, with their old-fashioned look, glowing filaments and sepia tones, are popular at restaurants and with modern home designers. Los Angeles Times, "UC Santa Barbara sues Walmart, Amazon and others over LED lightbulbs," 30 July 2019 The foundation team was able to track the pair for 25 minutes; what mesmerized was not only the procreative union but the halo of filaments that radiated outward from the female’s body, shimmering with points of light. William J. Broad, New York Times, "The Creepy Anglerfish Comes to Light. (Just Don’t Get Too Close.)," 29 July 2019 The mine was once used to produce an iron manganese tungstate mineral for craft light bulb filament. Dave Quinn,, "Instagram Influencers Sick After Swimming in Turquoise Lake That Is Actually a Toxic Dump," 25 July 2019

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

14 Sep 2019

Look-up Popularity

Time Traveler for filament

The first known use of filament was in 1594

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More Definitions for filament



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 How to pronounce filament (audio) \

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 How to pronounce filament (audio) \

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 How to pronounce filamentous (audio) \ 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).


formidable, illustrious, or eminent

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