RMS Power?

Erik, They could say Average Power - power equivalent to power produced by DC voltage of 0.707Vp.
There are no two different power values - average and rms as it is with voltage. There is only one power - Average Power.

I’m pretty sure that when you visit websites of all major amp makers like Pass Labs, Jeff Rowland etc - you won’t find terms "rms power" or "watts rms".

I don’t have big hopes for changing anybody’s mind on this forum (even FTC stayed ignorant for 25 years).

Wliliewonka - It is "watt" and not "Watt" (units start with small letter - but I’m sure you don’t care). You can go back to sleep now.

kijanki,
Even though I am completely ignorant on the subject, I can fully understand why the incorrect term bugs you. I'm glad that there are people like you around to make us aware of these things.
I'm expecting Almarg to jump into this any minute...

Faulty term watts rms or rms power came most likely from around 1975 FTC standard for power rating. FTC realized, that they goofed up and 25 years later in 2000 they corrected it .

http://www.n4lcd.com/RMS.pdf

I think Roy Lewallen explained it very well:
http://eznec.com/Amateur/RMS_Power.pdf
In his summary:

The equivalent heating power of a waveform is the average power.
The RMS power is different than the average power, and therefore isn’t the equivalent heating power. In fact, the RMS value of the power doesn’t represent anything useful.
The RMS values of voltage and current are useful because they can be used to calculate the average power.

Thank you roxy54.  Almarg is much better in explaining technical merits. I'm just trying to contribute something being grateful for all things I learn here.