Illumination is light that makes things visible, or the act of providing that light. When you flip a switch and flood a dark room with brightness, that's illumination. Street lamps provide illumination for nighttime drivers and pedestrians. Before electric lights, people relied on candles, oil lamps, and gas lights for illumination.

When something is illuminated, it becomes clear and understandable, no longer hidden in darkness. Scientists use illumination to study tiny organisms under microscopes. Museums carefully control the illumination of ancient paintings to protect them while letting visitors see the details.

Illumination also means sudden understanding or insight. When you've been puzzling over a difficult math problem and suddenly see how to solve it, that flash of comprehension is a kind of illumination. The medieval monks who decorated manuscript pages with gold leaf and intricate paintings created what we call illuminated manuscripts, bringing light and beauty to the written word.

Whether it's physical light brightening a space or mental clarity brightening your understanding, illumination reveals what was previously obscure or hidden.