filament

noun

fil·​a·​ment ˈfi-lə-mənt 

: 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

filamentary

ˌfi-lə-ˈmen-t(ə-)rē 

adjective

filamentous

ˌfi-lə-ˈmen-təs 

adjective

Synonyms of filament

• fiber
• wire
• thread

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

Then there's support for the optional Polar Cooler, which routes chilled air toward the extruder and filament path to reduce heat creep during hotter chamber operation—further reinforcing the Max 4’s focus on sustained high-temperature printing. — Michael Lydick, PC Magazine, 15 Aug. 2026

As a result, each filament is mostly limited to one type of movement. — Georgina Jedikovska, Interesting Engineering, 12 Aug. 2026

Inspired by spider silk, AMSilk uses fermentation to create silk proteins that are then turned into filaments. — Sarah Jones, Footwear News, 10 Aug. 2026

Out in the wild, turbulent air swirls these plumes into a chaotic, broken landscape—dense chemical filaments laced through long stretches of clean air. — Jacek Krywko, ArsTechnica, 1 Aug. 2026

Word History

Etymology

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

First Known Use

1594, in the meaning defined above

Rhymes for filament

• monofilament

Kids Definition

filament

noun

fil·​a·​ment ˈfil-ə-mənt 

: a single thread or a thin flexible threadlike object, process, or part: as

a

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

b

: a long chain of cells (as of some bacteria or algae)

c

: the anther-bearing stalk of a plant stamen

filamentous

ˌfil-ə-ˈment-əs 

adjective

Medical Definition

filament

noun

fil·​a·​ment ˈfil-ə-mənt 

: 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)

filamentous

ˌfil-ə-ˈment-əs 

adjective