CRT screen, also known as cathode ray tube screen, is an older technology that was used in computer monitors and televisions. There are various synonyms for CRT screen, including tube screen, monitor tube, display tube, and picture tube. These terms refer to the same type of display device that consists of a vacuum tube with an electron gun at one end that emits electrons to create an image on a fluorescent screen at the other end. While CRT screens have been replaced by newer technologies like LCD and LED screens, these synonyms can still be used to refer to this older type of display.