periscope

This device is defined by the ability to provide a line of sight while the observer remains hidden or physically separated from the target area. It relies on the physics of reflection to bend light, creating a visual bridge between a concealed location and an external environment.

In modern usage, the term extends beyond naval warfare to include specialized medical endoscopes or industrial inspection tools. These applications share the same core requirement of navigating narrow or obstructed spaces to achieve visual confirmation without dismantling the surrounding structure.