definition of
[brightness]

[1] #1 brightness n. the location of a visual perception along a continuum from black to white. wn

[2] #2 brightness n. [cleverness, smartness] intelligence as manifested in being quick and witty. wn

[3] #3 brightness n. [luminosity, brightness level, luminance, luminousness, light] the quality of being luminous; emitting or reflecting light; "its luminosity is measured relative to that of our sun". wn