a hollow cylinder, of any material, used for the conveyance of fluids, and for various other purposes; a pipe.-a telescope.-a vessel in animal bodies or plants, which conveys a fluid or other substance.-the narrow, hollow part of a gamopetalous corolla.-a priming tube, or friction primer. see under priming, and friction.-a small pipe forming part of the boiler, containing water and surrounded by flame or hot gases, or else surrounded by water and forming a flue for the gases to pass through.-a more or less cylindrical, and often spiral, case secreted or constructed by many annelids, crustaceans, insects, and other animals, for protection or concealment. see illust. of tubeworm.-one of the siphons of a bivalve mollusk.-to furnish with a tube; as, to tube a well.