What is the term for the bending of light?

The term for the bending of light is refraction. This phenomenon occurs when light travels from one medium to another, such as from air to water, causing its speed to change and consequently altering its direction. As light passes through mediums with different densities, the change in speed results in the light bending at the interface of the two materials. For example, when a straw is placed in a glass of water, it appears bent at the surface due to the refraction of light.

Other processes involving light behave differently. Reflection refers to the bouncing back of light when it hits a surface, diffraction involves the spreading of light waves when they encounter an obstacle or pass through a narrow opening, and dispersion describes the separation of light into its different colors, as seen in a prism. Each of these terms defines a unique optical behavior distinctly different from refraction, reinforcing why refraction specifically denotes the bending of light.