The tag wiki excerpt for the former says:
Ancillary circuitry added to a design that provides protection of the main circuitry to enable the main circuits continuing functioning. In some cases the protection circuitry is sacrificial, being destroyed or degraded in the act of protecting. But not all protection circuits may do this. Examples of faults protected against are: Overvoltage, ESD, overheating, Overloading (too high of a current draw) amongst others.
The tag wiki excerpt for the latter says:
A device, components, or safety measure designed to protect circuits from overvoltage, overcurrent, a combination of these; or the theory of same.
Is there any difference in these tags? Should they be made synonyms/merged?