luminosity has definitions from the field of physics
1
[ noun ] (physics) the quality of being luminous; emitting or reflecting light

Examples

"its luminosity is measured relative to that of our sun"

Used in print

(L. Don Leet and Florence J. Leet, editors, The World of...)

The luminosity of the water is now believed to have been caused by the stimulation of vast numbers of the luminescent organism Noctiluca_miliaris by the turbulence of the sea .

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