"brightnesses" in the noun sense
1. brightness
the location of a visual perception along a continuum from black to white
2. brightness, cleverness, smartness
intelligence as manifested in being quick and witty
3. luminosity, brightness, brightness level, luminance, luminousness, light
the quality of being luminous emitting or reflecting light
"its luminosity is measured relative to that of our sun"
Source: WordNet® (An amazing lexical database of English)
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