Ethon: Why is this episode called Ethon? Who or what is Ethon?
I don't know why they used the spelling Ethon, but Aethon is a Greek word which means burning. Also, in Greek mythology, it's an eagle which mocked Prometheus. Basically, the title of the episode a layered way of saying "the Prometheus will be destroyed in this episode." Good thing you didn't know what it meant, otherise the title would be a spoiler.
Here's the Wikipedia page for Aethon