From Longman Dictionary of Contemporary Englishfilamentfil‧a‧ment /ˈfɪləmənt/ noun [countable] 
TDa very thin thread or wire an electric filament
TDa very thin thread or wire an electric filamentExamples from the Corpus
filament• Surveys of galaxies show large voids with virtually nothing in them, and filaments and walls made up of clusters and superclusters.• The snake makes it wriggle so that the apparently disembodied filament appears to be some kind of succulent worm.• Notice that there are various places in Fig. 3. 3 where five filaments come together.• When the sheet is examined in the electron microscope filaments are seen to be localized at the upper surface.• Contained within the iris are thousands of nerve filaments.• In cooperation with nerve filaments, muscle fibers and blood vessels duplicate tissue changes, simultaneously with associated organs of the body.• Yank on one filament in the web, and the other filaments had to move, too.• As soon as that happens, the spider stops spinning, turns round, pulls the filament tight and secures it on her side.Origin filament (1500-1600) Medieval Latin filamentum, from Latin filum “thread” 