1. a unit of measurement for the amount of light produced by a light source
Usage: physics; technical
2. the hollow space inside a tube-like structure in the body
Usage: anatomy; medical

Examples

• This LED bulb produces 800 lumens of light.
• The new flashlight has a brightness of 1000 lumens.
• Higher lumen ratings indicate brighter light output.
• The doctor examined the lumen of the blood vessel.
• A blocked lumen can restrict blood flow.
• The catheter was inserted into the arterial lumen.