n. - The collection or mass of filaments growing from the skin of an animal, and forming a covering for a part of the head or for any part or the whole of the body.
n. - One the above-mentioned filaments, consisting, in invertebrate animals, of a long, tubular part which is free and flexible, and a bulbous root imbedded in the skin.
n. - Hair (human or animal) used for various purposes; as, hair for stuffing cushions.
n. - A slender outgrowth from the chitinous cuticle of insects, spiders, crustaceans, and other invertebrates. Such hairs are totally unlike those of vertebrates in structure, composition, and mode of growth.
n. - An outgrowth of the epidermis, consisting of one or of several cells, whether pointed, hooked, knobbed, or stellated. Internal hairs occur in the flower stalk of the yellow frog lily (Nuphar).
n. - A spring device used in a hair-trigger firearm.
n. - A haircloth.
n. - Any very small distance, or degree; a hairbreadth.