luminosity

Meanings

1. 1
   noun

   the quality or degree of giving off or reflecting light; brightness

   The moon's apparent luminosity increased as the clouds cleared.

2. 2
   noun

   in astronomy, the total rate at which a star or other object emits energy

   The astronomers estimated the star's luminosity from its spectrum and distance.

Borrowed from French luminosité or formed from luminous with -ity, ultimately from Latin lūmen, 'light.' Astronomy gave the general quality of brightness a precise sense: an object's intrinsic rate of energy emission.

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