What does the term 'refraction' specifically refer to in the context of light?

Refraction occurs when light travels from one medium to another and changes its speed, leading to a change in its direction. This change of speed happens because different materials have varying optical densities, which affects how quickly light can pass through them. For example, light moves more slowly in water than in air, and when it enters the water from air, it bends at the interface, illustrating the phenomenon of refraction.

This bending of light is crucial in many optical applications, such as lenses in glasses or cameras, where controlling the direction of light is essential for proper focus and image clarity.

Other terms like reflection (light bouncing off a surface), absorption (light being taken in by a material), and dispersion (light spreading out into a variety of colors) describe different interactions between light and matter but do not accurately capture the specific behavior of light changing direction due to variations in speed brought about by different media, which is the essence of refraction.