An anti-glare screen is a screen that does not reflect the light. An anti-glare screen can easily be used outside when the sun is shining, as opposed to a glossy screen.
Glare means the reflection of light from a source (such as the sun) off a window or a screen. This makes it difficult to see what is happening on the screen. With the help of a thin coating, a so-called Anti-Glare screen coating, these glare effects can be reduced. Originally, LCD displays had a non-glare (anti-glare) matte finish, which meant that they did not reflect light. Later on, LCD displays used another screen finish called a glossy finish, which enhanced the colors but in turn made the display reflective.
So for color, a glossy display will look better than a display with an anti-glare screen. In very bright areas, such as outside when the sun is shining, the anti-glare screen will be better to use since you will have a difficult time seeing what’s going on in your glossy display.