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 tube. Cathode-ray tubes are used to study the shapes of electric waves, to reproduce images in television receivers, to display alphanumeric and graphical information on computer monitors, as an indicator in radar sets, etc. Abbr.: CRT