What does the term "refraction" describe?

The term "refraction" describes the bending of waves as they pass from one medium into another due to a change in their speed. When waves travel through different materials, such as from air into water, their velocity changes depending on the properties of the media. This change in velocity leads to a change in direction, which is clearly observed with light, sound, and other types of waves.

In the context of refraction, the law of refraction, known as Snell's law, quantitatively describes how the angle of incidence and the angle of refraction relate to the speed of waves in different media. The bending effect is responsible for various phenomena, such as the apparent bending of a straw in a glass of water or the way objects appear distorted when viewed through glass or water.

While reflection involves waves bouncing off surfaces and absorption refers to the loss of energy as waves are taken in by a medium, these processes do not involve the change in direction due to a difference in media. The change in frequency relates to phenomena such as the Doppler effect, which differs from the bending caused by refraction. Therefore, the correct answer accurately encapsulates the specific nature of refraction.