A lumen is a unit of measurement used to quantify the amount of visible light emitted by a source. It helps to describe how bright a light bulb or other lighting device appears to the human eye. The higher the lumen rating, the brighter the light. For example, a standard 60-watt incandescent bulb typically produces about 800 lumens. In the context of lighting, lumens are important for choosing the right brightness for different spaces. For instance, a living room may require more lumens for general illumination, while a bedroom might need fewer lumens for a softer, more relaxing atmosphere.