Final answer:
The limit to how much reverse voltage a diode can withstand is known as the breakdown voltage. This is the voltage beyond which the diode conducts in reverse bias and at which it may be damaged.
Step-by-step explanation:
The limit to how much reverse voltage a diode can withstand before it is destroyed is called breakdown voltage. When a diode is in reverse bias, very little current flows through it until the applied voltage reaches the breakdown voltage; beyond this point, the diode conducts current. The forward bias of a diode occurs when it conducts current easily because the anode is positive relative to the cathode, but this is not related to the diode's maximum reverse voltage capacity.