- An electronic device that restricts current flow chiefly to one direction.二极管：将电流主要限制于一个方向的电子设备
- An electron tube having a cathode and an anode.电子二极管：有一个阳极和一个阴极的电子管
- A two-terminal semiconductor device used chiefly as a rectifier.半导体二极管：主要作为整流器使用的一个有两端的半导体设备