Filament may refer to any of the following:
Filament refers to a wire used for conducting electricity, forming part of a vacuum tube or light bulb. The picture shows the filament of an incandescent light bulb.
When referring to a 3D printer, filament is the material used to form the printed object. The 3D printing filament is usually made from ABS (acrylonitrile butadiene styrene) or PLA (polylactic acid).
Electronics terms, Hardware terms