Real Dictionary

cathode ray tube in Electrical Engineering
noun: A cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen, that is used to display images.

cathode-ray tube
countable noun: A cathode-ray tube is a device in televisions and computer terminals which sends an image onto the screen.

cathode-ray tube in American English
a vacuum tube in which a stream of electrons is electromagnetically focused on a fluorescent screen, producing lighted dots: such tubes are used as oscilloscopes and picture tubes: abbrev. CRT
noun: a vacuum tube generating a focused beam of electrons that can be deflected by electric fields, magnetic fields, or both. The terminus of the beam is visible as a spot or line of luminescence caused by its impinging on a sensitized screen at one end of the

cathode-ray tube in British English
noun: a valve in which a beam of high-energy electrons is focused onto a fluorescent screen to give a visible spot of light. The device, with appropriate deflection equipment, is used in television receivers, visual display units, oscilloscopes, etc