Noun
The quality or state of being bright; splendor; luster; brilliancy; clearness.
Acuteness (of the faculties); sharpness 9wit.
Source: Webster's dictionaryits luminosity is measured relative to that of our sun Source: Internet
A backlight sits behind these keys, but there's only one brightness level. Source: Internet
According to the classical theory of light and matter, the strength or amplitude of a light wave was in proportion to its brightness: a bright light should have been easily strong enough to create a large current. Source: Internet
Additionally, in an expanding universe, distant objects recede from us, which causes the light emanating from them to be redshifted and diminished in brightness. Source: Internet
Although you would normally expect to see around 60 meteors per hour during the peak phase, NASA that this year the brightness of the moon will impede the view somewhat, reducing the visible meteors to around 20 per hour. Source: Internet
Also, the geometric albedo of Chiron's rings as determined by spectroscopy is consistent with that used to explain Chiron's long-term brightness variations. Source: Internet