In physics and electrical engineering

• An electrical filament used to emit light in an Incandescent light bulb
  Incandescent light bulb
  The incandescent light bulb, incandescent lamp or incandescent light globe makes light by heating a metal filament wire to a high temperature until it glows. The hot filament is protected from air by a glass bulb that is filled with inert gas or evacuated. In a halogen lamp, a chemical process...
  
  
• Similarly, a thin heating element
  Heating element
  A heating element converts electricity into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element....
  
  
• Current filament
• Filament propagation
  Filament propagation
  In nonlinear optics, filament propagation is propagation of a beam of light through a medium without diffraction. This is possible because the Kerr effect causes an index of refraction change in the medium, resulting in self-focusing of the beam....
  
  , diffractionless propagation of a light beam
• Hot cathode
  Hot cathode
  In vacuum tubes, a hot cathode is a cathode electrode which emits electrons due to thermionic emission. In the accelerator community, these are referred to as thermionic cathodes. The heating element is usually an electrical filament...
  
  , a filament in a vacuum tube that emits electrons

In astronomy

• Galaxy filament
  Galaxy filament
  In physical cosmology, galaxy filaments, also called supercluster complexes or great walls, are, so far, the largest known cosmic structures in the universe. They are massive, thread-like structures with a typical length of 50 to 80 megaparsecs h-1 that form the boundaries between large voids in...
  
  , the largest known cosmic structures in the universe, thread-like structures that form the boundaries between large voids in the universe
• Solar filament, equivalent to a solar prominence
  Solar prominence
  A prominence is a large, bright feature extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the Sun's corona...
  
  
• Birkeland current
  Birkeland current
  A Birkeland current is a set of currents which flow along geomagnetic field line connecting the Earth’s magnetosphere to the Earth's high latitude ionosphere. They are a specific class of magnetic field-aligned currents. Lately, the term Birkeland currents has been expanded by some authors to...
  
  , a specific magnetic field-aligned current in the Earth’s magnetosphere

In biology

• Protein filament
  Protein filament
  In biology, a filament is a "long chain of proteins, such as those found in hair, muscle, or in flagella". They are often bundled together for strength and rigidity. Some cellular examples include:*Actin filaments*Microtubules*Intermediate filaments...
  
  , a long chain of protein subunits, such as those found in hair, muscle, or in flagella
• Part of a stamen
  Stamen
  The stamen is the pollen producing reproductive organ of a flower...
  
  , the male part of a flower
• A chain of cells connected end-to-end
• Hypha
  Hypha
  A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
  
  , a thread-like cell in fungi and Actinobacteria
• Filamentation
  Filamentation
  Filamentation is the anomalous growth of certain bacteria, such as E. coli, in which cells continue to elongate but do not divide . Bacterial filamentation is often observed as a result of bacteria responding to various stresses, including DNA damage or inhibition of replication...
  
  , an elongation of individual bacterial cells

Other uses

• Fiber
  Fiber
  Fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....
  
   or yarn
  Yarn
  Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery and ropemaking. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or...
  
  
• Staple (wool), clusters or locks of wool fibers
• 2002 movie by Jinsei Tsuji
• Filament (band)
  Filament (band)
  Filament is a musical group from Japan that consists of Otomo Yoshihide and Sachiko M, two of the major exponents of the electroacoustic improvisation style of music....
  
  , a musical group from Japan that consists of Otomo Yoshihide and Sachiko M
• Filament Games
  Filament Games
  Filament Games is a Madison, Wisconsin based educational video game developer founded in 2005 by partners Daniel White, Daniel Norton, and Alexander Stone. The company is most well known for their series of civics games launched by Sandra Day O'Connor for iCivics, her civics-education initiative...
  
  , a Madison, Wisconsin based educational video game developer
• Filament Productions
  Filament Productions
  Filament Productions is a Production Design & Touring Video company based in Charlottesville, Virginia since 2005, and founded by Fenton Williams, who was the first road manager for the Dave Matthews Band. During the early 1990s Fenton Williams quickly realized he wasn't the best road manager and...
  
  , a Production Design & Touring Video company based in Charlottesville, Virginia