brightness in WordNet English dictionary

1. the location of a visual perception along a continuum from black to white
   brightness 
   
2. the quality of being luminous; emitting or reflecting light
   "its luminosity is measured relative to that of our sun"
   luminosity  brightness  brightness level  luminance  luminousness  light 
   
3. intelligence as manifested in being quick and witty
   brightness  cleverness  smartness