Luminous
Etymology
From Latin "luminosus" ("full of light"), from "lumen" ("light"), which is related to "lucere" ("to shine"). It came into English through Old French. The core sense — giving off or reflecting light — has stayed remarkably stable across the centuries.
adjective · /LOO-mih-nus/
Full of or reflecting light, so that a thing seems to glow.
What it names
The soft, radiant quality of something that appears to give off a gentle light of its own — a face, a painting, a moonlit sky.
Example
The pearl had a luminous sheen that seemed to gather what little light was in the room.
Related idea
Radiant also means shining, but radiant suggests light beaming outward with energy, while luminous suggests a steadier, softer glow.