Bolt action is a term used to describe a particular type of
small arm. Specifically, it refers to the method used for ejecting cartridges,
stripping and loading rounds, and
cocking the action. A bolt action rifle has a metal cylinder (the bolt) placed behind the firing chamber. This cylinder rides inside the rear of the barrel, and a slot allows a handle to project off to one side. Typically, the action of gripping the handle and pushing it forward to ram home a cartridge is followed by rotating it down to 'lock' the chamber and
cock the action.
Webby has a bunch of definitions for bolt; the two that look most applicable to the root of this word are:
3. A strong pin, of iron or other material, used to fasten or hold something in place, often having a head at one end and screw thread cut upon the other end.
4. A sliding catch, or fastening, as for a door or gate; the portion of a lock which is shot or withdrawn by the action of the key.
In this case, the 'strong pin' is used to hold the
round or
cartridge in place and lock it there so that it can be fired. After the
weapon is
discharged (another meaning of 'bolt' is 'to spring forth, to fire as an arrow') then the bolt is operated manually by lifting the handle (rotating the bolt counterclockwise and unlocking it) and then pulling back. A mechanism inside the chamber causes the now-empty
cartridge casing, as it is drawn back, to
eject itself from the chamber so as to ready the weapon for the next cartridge.
Some other methods of rifle operation include semi-automatic, both gas-operated and recoil-operated, as well as lever-action (popularized by the Winchester Semi-automatic rifle popular in Westerns, as well as on the Terminator's shotgun in the second flick). Pump-action has been used in rifles; Chase pointed me at the Remington 760 Gamemaster line, which comprises several gun types in a wide range of calibers manufactured between 1952 and 1981. This used what Remington called a 'slide action,' which was worked via a pumping motion using a grip mounted beneath the barrel in a similar location to a shotgun pump.
In earlier times, the harquebus and interrupted screw mechanisms were used to ignite the charge and hold the round in the chamber, among other schemes.