What does "CRT" stand for?

"CRT" is an acronym for cathode ray tube. It is an evacuated tube used primarily for monitors, although it is largely obsolete as of 2014. Most newer monitors use light emitting diodes or a liquid crystal display.

CRT monitors have a general boxlike shape and cannot be thin flat screens like the modern LED and LCD. This is because of the funnel-shaped vacuum tube that channels the cathode ray to the phosphor screen seen by the viewer. The tube is encased inside coiled wires that create a magnetic field, which acts on the electrons inside and directs them to specific points on the screen to form the images on the monitor.