I take it that these are amplifier terms? PMPO?? I have no frickin clue! Peak would probably be the peak wattage the amp will put out. A very bad stat to look at because you will never see the amp put out that much power, and if you do, it will be hella distorted.
Peak Music Power Output or Peak Momentary Power Output are what PMPO are.
Peak is the maximum power output of the device under perfect conditions and 100% efficiency. This is impossible to obtain, and no amp can sustain the PMPO power for any significant length of time without frying.