It is the amount of "shades" the LCD screen can show between pure white and black…
No, the number of shades the monitor can display is a function of the video card, and in any event all consumer RGB monitors display the same number of shades (256 discrete shades in each of the three color channels, for a total of just over sixteen million discrete colors).
It is a measure of the difference in brightness between the darkest black and brightest white the monitor displays–that is, a measure of *contrast*–not a measure of the number of shades of color the monitor can display. —
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