Pronunciation: (lOO"mu-nos'i-tē), [key]
1. luminance (def. 2).
2. the quality of being intellectually brilliant, enlightened, inspired, etc.: The luminosity of his poetry is unequaled.
3. something luminous.
4. Astron.the brightness of a star in comparison with that of the sun: the luminosity of Sirius expressed as 23 indicates an intrinsic brightness 23 times as great as that of the sun.
5. Also called luminos'ity fac"tor. Optics.the brightness of a light source of a certain wavelength as it appears to the eye, measured as the ratio of luminous flux to radiant flux at that wavelength.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.