What is "luminous flux"

n. In photometry, the measure of the power of light as perceived by the human eye, in proportion to the power at each wavelength.

n. the rate of flow of light energy

In photometry, luminous flux or luminous power is the measure of the perceived power of light. It differs from radiant flux, the measure of the total power of electromagnetic radiation (including infrared, ultraviolet, and visible light), in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light.