Power Metal Battle: US vs Euro

Power metal as a term originated in the US, to describe the heavier bands from say Iron Maiden, Sababth, U.F.O, Riot, Priest, the Scorpions, Whitesnake, NWOBHM bands, you know, the heavy metal bands of the beginning of the 80s. The term just meant "intense heavy metal" (faster, heavier or both) and it was adopted by the younger generation as evidenced by the Metallica demo Jasonic mentioned. I'm not aware of who first coined the term and how widespread it was at the beginning. 

I do know that it was used by fans in the US (I've talked to some and the testimonies here confirm it) for a mixture of bands, who by todays standards could be labelled as heavy, power, speed or thrash metal. In short, at the beginning the term was used rather loosely. 

It definitely got used to describe the more melodic thrash metal bands, like early Overkill, Metallica's Ride the Lightning, Metal Church etc. If at this point it was used to describe Jag Panzer, I do not know, maybe Mark can shed some light on that. 

Speed metal was also a term used interchangeably. It was used to describe fast metal, whether it was fast heavy metal like Raven, Anvil, the faster Venom songs or the new generation of thrash metal bands, like Kill Em All, Fistful of Metal, Megadeth of course (who had the classic backprint slogan "world's state of the art speed metal"). Thrash got big, so speed metal for the better part of the 80s meant "thrash metal", before that term (around 86-87) got globally embedded to the metalhead's vocabulary. 

Speed metal on the other hand got abandoned, primarily because musicians hated the trend of trying to be faster than anyone else, the term soon felt derogatory to them. I remind you of the Cliff Burton quote that they don't need to play at a thousand miles per hour. Slayer, after destroying all competition with Reign in Blood and the two de facto thrash anthems from that album, proceeded to release the (doom by their standards!) South of Heaven. 

Power metal in Europe wasn't really adopted until the Keepers. A logical transition, since their seminal speed metal debut (literally speed and a fine example of power metal melody combined with thrash metal intensity and heaviness) fitted the power metal definition of the Americans. When they dropped the speed and the intensity, it was the only logical term to describe their music. The term was adopted for the entire booming German scene at the time of which Helloween was the most successful (and arguably the best), at first they were called interchangeably power, speed, even thrash(see Running Wild and Rage but also Iron Angel, Angel Dust, Scanner, Blind Guardian etc) and slowly that stabilized to power metal, after speed metalwas ousted from mainstream vocabulary (a shame). 

From that point onwards, at least in Europe power metal stopped being a synonym for early melodic thrash bands and instead got used for the bands that were more intense than the aforementioned heavy metal bands. So, Jag Panzer, early Queensryche, Vicious Rumors, Savatage, Crimson Glory, Leatherwolf, Oliver Magnum, early Helstar etc, around mid to late 80s, at least in Europe were the US Power Metal scene and remain to this day, at least in Greece, where we take all this shit very seriously indeed. We never adopted the german terms (melodic metal or true metal or any of those).