[PrimeDirective]

> Calling them "power chords" in a non-rock context sounds off to me, though

Even jazz musicians call them powerchords

[H1Supreme]

Every guitar player calls them powerchords. I've never heard of another term. Unless OP is referring to double stops. But, those are more of an embellishment, and usually never played on the low E or A string.

[taylodl]

Jazz, rock, and pop guitarists and keyboardists all call 5 chords power chords.