To be honest, not being very familiar with the word, I was guessing that the wavefront was the front (the closest part) of a wave, which, in this case would be first light. But, having looked it up, I see it doesn't mean what either us have taken it to mean.

The Oxford dictionary gives wavefront as, "a surface containing points affected in the same way by a wave at a given time." And if, as I did, you want some elaboration, here's a fuller definition: "A wavefront is an imaginary surface representing corresponding points of a wave that vibrate in unison. A wavefront is the set of all locations in a medium where the wave is at the same phase. This could be where all the crests are, where all the troughs are, or any phase in between.".

Now that's clearly a definition from Physics, but it's the only definition I can find.

Obviously, this is poem, so you're not bound by the strict definition of words. That said, since it's a technical term from Physics, maybe it's not the best choice here.

Matt

If what I got from the word is purely subjective—and it’s beginning to look like that—I agree completely.