resolution

Resolution defines the amount of pixels (dots) contained by the entire monitor, it defines the image quality of the certain screen.

The images are formed by the great amount of colorful dots called pixels. They are not noticeable on the screen due to their tiny size.

The amount of pixels usually includes tens of millions dots that give us a perfect illusion of the sharp image.

High resolution means that the image was created using more pixels, that leads to a cleaner, sharp image.

Low resolution image would be showing up pixelized on the high resolution monitors, because the same amount of pixels is spreading out over a bigger amount of inches.

You can find more details about Resolution following this link.