A nimbus is a glowing circle of light that appears around the head of a holy or divine figure in religious art. When you look at paintings of saints, angels, or other sacred figures, you'll often see a bright golden disk or ring floating behind their heads. That's a nimbus, and it's the artist's way of showing that this person is holy, blessed, or connected to the divine.

You might also hear the word halo used to mean the same thing, though nimbus is the more formal, traditional term. In meteorology, a nimbus cloud (or nimbostratus) is a dark, heavy cloud that brings rain.

When someone acts extremely good or innocent, people sometimes joke about them having a nimbus or halo. If your friend refuses to join in when others are breaking the rules, someone might tease them about their “halo shining bright,” suggesting they're acting self-righteous.