Light Output

The luminous flux, or light output, is defined as the total quantity of light emitted per second by a light source (bulb). The unit of luminous flux is the lumen (lm).

For example, BAZZ recessed fixture CFL 400 with a GU24 23W compact fluorescent bulb (equivalent to a 100W incandescent bulb) indicates a total light output of 1600 lumens. 

Information from Natural Resources Canada - Lighting Reference Guide.