What is Resolution?
Screens are made up of tiny addressable squares or pixels. If you look closely at your monitor, you’ll see these tiny squares made up of (usually) Red, Green, and Blue lines. The Red, Green, and Blue lights mix to produce a colored light; the collection of these colors work like a huge patchwork quilt to produce the image you’re looking at right now.
Resolution is the number of these pixels wide by the number of pixels high that your screen displays.
i.e. 1920 x 1080 resolution is 1,920 pixels wide and 1,080 pixels high and is referred to as “nineteen twenty by ten eighty.”