1. the quality or state of giving off or reflecting light; brightness
2. the quality of being clear and easily understood; clarity of thought or expression
Usage: figurative

Examples

• The luminousness of the full moon lit up the entire landscape.
• Scientists measured the luminousness of different star types.
• The diamond’s luminousness caught everyone’s attention.
• Her essay was praised for its luminousness and clear reasoning.
• The luminousness of his explanation helped students understand the concept.
• The painting captured the luminousness of morning sunlight on water.