A (usually) metal fastener consisting of a cylindrical body that is threaded, with a larger head on one end. It can be inserted into an unthreaded hole up to the head, with a nut then threaded on the other end; a heavy machine screw. • Latch-related senses • A sliding pin or bar in a lock or latch mechanism. • A bar of wood or metal dropped in horizontal hooks on a door and adjoining wall or between the two sides of a double door, to prevent the door(s) from being forced open. • A sliding mechanism to chamber and unchamber a cartridge in a firearm. • An iron to fasten the legs of a prisoner; a shackle; a fetter. • A stalk or scape (of garlic, onion, etc). • A large roll of fabric or similar material, as a bolt of cloth. • The standard linear measurement of canvas for use at sea: 39 yards. • Senses involving sudden movement • A small personal-armour-piercing missile for short-range use, or (in common usage though deprecated by experts) a short arrow, intended to be shot from a crossbow or a catapult. • A lightning spark, i.e., a lightning bolt. (See thunderbolt.) • A sudden event, action or emotion. • A sudden spring or start; a sudden leap aside. • A sudden flight, as to escape creditors. • A refusal to support a nomination made by the party with which one has been connected; a breaking away from one's party. • A burst of speed or efficiency.