Lumens are a unit of measurement used to describe the brightness of a light source. However, there are several synonyms for the word "lumens" that can be used to describe the brightness of a light source. For example, candela is another unit of measurement that is used to describe the brightness of a light source, but it measures the intensity of light in a specific direction. Lux is another synonym for lumens, and it is used to describe the amount of light that falls on a surface. In addition, the term "brightness" can be used as a synonym for lumens to describe the overall intensity of a light source.