- diode, rectifying tube, rectifying valve - a thermionic tube having two electrodes; used as a rectifier
--1 is a kind of tube, vacuum tube, thermionic vacuum tube, thermionic tube, electron tube, thermionic valve
- diode, semiconductor diode, junction rectifier, crystal rectifier - a semiconductor that consists of a p-n junction
--2 is a kind of semiconductor device, semiconductor unit, semiconductor
--2 has particulars: light-emitting diode, LED