Radiance is a glowing brightness that seems to shine outward from something. When sunlight streams through a window on a clear morning, filling the room with warm light, that's radiance. When you look at pictures of the sun, you see its radiance spreading in all directions.

It captures that sense of light spreading outward like the spokes of a wheel. Scientists use radiance to measure how much light energy something gives off.

Radiance also describes the visible glow that comes from inner joy or vitality. When someone is genuinely happy or healthy, we might say their face has a certain radiance: they seem to glow from within. A bride on her wedding day, an athlete who just won a hard-fought competition, or your friend who finally solved a problem they'd been working on for weeks might all show this kind of radiance. It's that visible brightness that comes from feeling proud, joyful, or deeply satisfied.

The adjective form is radiant. You might describe a radiant sunset, a radiant smile, or someone with radiant confidence. When something or someone is radiant, they seem to be the source of light or happiness, spreading it outward to others.