n. A fine untwisted thread; a separate fiber or fibril of any vegetable or animal tissue or product, natural or artificial, or of a fibrous mineral: as, a filament of silk, wool, cobweb, or asbestos; a cortical or muscular filament.n. Specifically In botany, the support of an anther, usually slender and stalk-like, but very variable in form.n. In ornithology, the part of a down-feather corresponding to the barb of an ordinary feather.n. A tenuous thread of any substance, as glass or mucus; hence, in medicine, a glairy substance sometimes contained in urine, capable of being drawn out into threads or strings.n. The nearly infusible conductor placed in the globe of an incandescent lamp or glow-lamp and raised to incandescence by the passage of the current. It is usually some form of carbon, although metals with high points of fusion have been used.n. In geometrical topics, a movable object which at any one instant, or indivisible determination of time, is at every part of a line. During a lapse of time a filament is restricted to being in some surface, which it is said to generate.n. A long threadlike bacterial growth.