telescopic sight

A telescope is a magnification tool used to visually enlarge objects. "Telescopic" refers to the ability of a device to visually enlarge objects. A telescopic sight, for example is a small telescope mounted on a firearm in order to increase accuracy of aim, often referred to simply as a “scope.”

Telescopic also refers to the mechanical ability of a device to extend or contract in length. Some ladders are telescopic, for example, and can be raised or lowered in height as necessary.