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 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 fit
Weaver rail mount
…A Weaver rail mount is a system to connect telescopic sights (often via a scope mount) and other accessories to firearms and certain crossbows. It uses a pair of parallel rails and several slots perpendicular to these rails. The later…
A Leupold telescopic sight mounted on a dovetailed rifle receiver via two scope rings
A scope with integral mount on a Heckler & Koch PSG1
An LPS 4×6° TIP2 scope with integral side-mount on a Romanian PSL rifle
An old German machinegun telescopic sight with scope rings