What is the RMS reverse voltage for diodes?
Clabbachio is correct for a sinewave and that is how the datasheet specifies the voltages. It is the peak voltage that should never be exceeded as this will breakdown the diode junction.


Other voltage waveforms will have different values for peak and rms. (for example  in a power converter where signals are switch pulses.) The r.m.s. value can be quite low compared to the peak voltage.


In these cases the diode must be chosen to withstand the peak reverse voltage.