What does the word luminosity mean?

Usage examples for luminosity

  1. Plated with some metallic substance that was itself a reservoir of luminosity and from which, it came to me, pulsed the force that lighted the winking ions. – The Metal Monster by A. Merritt
  2. At an altitude of 2, 150 feet the air- liner slid out over the Sea, the waters of which shone in the mid- afternoon sun with a peculiar luminosity. – The Flying Legion by George Allan England