Plain English Meaning

The wave's path is bent rather than continuing in a straight line. When a radio signal travels upward and hits the ionosphere, it doesn't just keep going into space — its direction is changed, often enough to send it back down to the ground.

Full Definition

Bent from its original straight path as it passes from one medium into another of different density, or through a medium whose density changes. In radio propagation, a sky wave is refracted when it enters the ionosphere and the change in electrical density bends the wave back toward Earth.

Context Anchor

Seen in basic radio principles when explaining sky waves and how some radio signals can travel beyond the normal straight path from the transmitter.

Derivation

From the Latin refractus, meaning 'broken back.' The idea is that the wave's path is 'broken' at the boundary and bent in a new direction — not snapped, but redirected.

Why Pilots Care

Refraction determines how an HF signal travels and whether it returns to earth for long- beyond .