"Double-action" refers to a mechanism commonly found in firearms, particularly revolvers. In a double-action firearm, pulling the trigger performs two actions: it cocks the hammer and then releases it to fire the bullet. This allows for quicker shooting since the shooter does not need to manually cock the hammer before each shot. In addition to firearms, the term "double-action" is also used in other contexts, such as in certain types of machinery and tools. For example, a double-action pump can push fluid in both directions, making it more efficient for tasks like inflating tires or moving liquids.