The term 'Vacuum Tube Type' refers to three different types of vacuum tubes: a triode (6 letters), a DIODE (5 letters), and a cathoderay (10 letters). A triode is an electronic device consisting of three electrodes, which can be used to amplify signals. A DIODE is a two-terminal electronic component that allows current to flow in one direction only. A cathoderay tube is a vacuum tube that uses a focused beam of electrons to create an image on a phosphorescent screen. All three of these vacuum tubes are used in various electronic applications.