Breech-loading refers to firearms that load ammunition from the rear or breech end of the gun rather than loading from the muzzle end. Synonyms for the term can include breech-fed, rear-loading, or breech-mechanism. Other related terms include bolt action, lever action, and pump-action firearms, which also use mechanisms to load ammunition from the rear. These terms are often used interchangeably, but they can refer to different types of guns. Overall, the term breech-loading remains the most commonly used term to describe firearms that load ammunition from the breech end.