The term "flat screen" refers to a type of display technology where the monitor or screen is thin and has no protruding parts. It means that the screen is mounted on a flat surface, such as a wall or a stand, without any bulging or protrusions. This type of display became popular in the early 2000s with the advent of LCD screens, which replaced older CRT displays. The term "flat screen" has become synonymous with modern and sleek displays that take up less space than their predecessors while providing high-quality images.