Wordology, Lock, Stock, and Barrel

This means everything, the whole thing. The term lock, stock, and barrel refers to the parts of a gun. There are three major parts of a gun, the lock or firing mechanism, the stock or wood handle, and the barrel which the bullet travels through. If one has a lock, stock, and barrel, then one has everything that makes up a gun. In time, the phrase came to be used figuratively to mean the whole thing.