refraction

This term describes the physical bending of a wave when it enters a new medium at an angle, causing a shift in its perceived position or direction. It is most commonly associated with the visual distortion seen when a straw appears broken in a glass of water.

In optical engineering, the term refers specifically to the controlled manipulation of light through lenses to focus images. This distinguishes it from reflection, where light bounces off a surface, and diffraction, where light bends around an obstacle.