GhostwriterDoF: I took it to mean Jupiter, but I already looked it up (before I posted) to see if you might have meant anything else...
I may be a yank, but I am part English too, though I've never walked under those skies. heh!
You are correct, it is indeed another name for Jupiter (the Roman God). I think it was his original name, but my Roman mythology is a little rusty. It was used as an expression of the most powerful of deities, at least in the context of the play.
tinyE: Maybe it was 'Job'.
I guess it depends on which Bible, as you Americans sure did love making up new religions after your independence, or rewriting the Christian Bible to better suit your needs. :-)
Edit: But Job is a book from the Bible, I think.