Linked from
The 13 pages that link to Diode, each with the reason it gives.
ElectronicsBroader topic: Its one-way conduction enables rectification and signal shaping.
Forward biasNarrower topic: Forward bias is the diode’s principal conducting condition.
Diode bridgeNarrower topic: Each bridge element directs current along a permitted path.
Vacuum electronicsBroader topic: A vacuum diode uses an anode and cathode to rectify current.