Burn

I don't think I actually saw the word "empyrean" today, but something brought it to mind nonetheless. The first three quarters of it look kind of like "empire", no, in the same way that "vampyre" is sometimes used as an alternate spelling for "vampire"? And you could even convince yourself if you tried that "empyrean", which looks like an adjective (and can be) but is also a noun meaning "the firmament of the heavens", could be etymologically related to "empire", if you figure that the sky, or Heaven, is a sort of empire ruled over by a god or a bunch of gods.

Yeah, you could do that. But you'd be wrong.

What else does "empyrean" look like? Maybe the prefix "em-" plus "pyre", as in "funeral pyre", as in "fire"?

It makes perfect sense when you know that in Greek cosmology, the highest of the heavens was the realm of pure fire (it's where the sun and the stars are), and "pyros" is indeed the (or at least a) Greek word for fire.