Gurren Lagann fans: What exactly is "spiral power"?

[cumbriancucumber@lemmy.world]

(spoiler warning)

I feel really stupid for having to ask this after seeing the Gurren Lagann recap movies, but what exactly is this "Spiral Power" that the show starts referring to in its second half? Throughout the whole anime, the main character Simone's favourite weapon is a drill, so in a literal sense, he's physically using the power of a spiral to fight.

But as the show goes on, it's revealed that humans are "spiral beings", meaning they're capable of using spiral power, among other spiral beings in the multiverse. Drills can shoot lasers as part of their spiral power, creatures that hang out with spiral beings can withhold spiral power of their own, and the main antagonists fear that the use of spiral power will lead to the destruction of the universe??

Was there an explanation to this that I totally missed or something? Is spiral power still something that comes primarily from Simone's drill? Is it more of a Dragonball-style energy wave that you're not supposed to think too hard about? Does it refer to the spiralling power upgrades that the characters go through, and it's meant to be a metaphor for humanity's ability to self-improve? Does it not really matter in an anime that's more about the character's ability to break through anything with sheer testosterone and willpower? Is it all meant to be left up to interpretation? I swear, I've seen this anime twice and now the recap movies too, and I STILL have no idea what it's about!