actually the most abused term i've seen is WATTS. especially the "Peak Music Power" kind. take an ordinary 50Wrms/channel 5.1 surround amp, measure the total rail voltage (+/-45V=90V), then measure the short circuit current of the power supply (10A is good, if measured just before the fuse blows). this gives you the Watts PMPO of the amp equalling 900W. then add the sales department's "fudge factor" to get a nice round number of 1000W. for 5 channels, this equals 200W/ch, but the 1000W looks better on the box. db's aren't very useful for sales departments, since the log function limits the size of db measurements to 2 digits, and rarely 3 digits.