The phrase "screen brightness" refers to how much light a screen emits. It determines how vivid and visible the images and text appear on the screen. Full definition
You can use these to adjust screen brightness with a swipe. (netbooknews.com)
The relatively high screen brightness set during the test means you could easily get more if you adjust the settings, and even so, nearly nine hours is a very respectable outcome. (techspot.com)
This helps save battery life and makes playing around with screen brightness less of a necessity. (mobilesyrup.com)