WordWeb Online

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

See also: bright, dull

Type of: intelligence, light, lightness, physical property

Antonym: dullness

Encyclopedia: Brightness