Filaments are thin strands of material that can be found in a variety of forms. Hairs, with five letters, are one type of filament that is composed of dead cells and proteins. Fibers, with six letters, are another type of filament that are usually made from natural or synthetic materials. THREADS, with seven letters, are a type of filament that is made up of multiple fibers twisted together. All three terms, hairs, fibers, and THREADS, can be used to describe the term filaments.