A Weaver rail mount is a system to connect telescopic sights and other accessories to firearms and certain crossbows. It uses a pair of parallel rails and several slots perpendicular to these rails.

Scope mounts are rigid implements used to attach (typically) a telescopic sight or other types of optical sights onto a firearm. The mount can be made integral to the scope body or, more commonly, an external fitting that clamp onto the scope tube via screw-tightened rings. The scope and mount are then fastened onto compatible interfaces on the weapon. Words such as mounts and bases are used somewhat loosely, and can refer to several different parts which are either used together or in place of each other as ways to mount optical sights to firearms.