SCREW

In Architecture, a piece of wood, iron, or other metal, pierced cylindrically, wherein is cut a spiral groove, adapted to an external cylindrical spiral cut on a bolt. Its use is to screw two bodies together, a head being placed on one end of the bolt to counteract the action of the nut. Two bodies are thus held together by compre ion, the bolt between the head and the nut being a tie. [s. 847]