Where does the word abracadabra come from?

Websters says, "unknown origin".

AHD says, "late latin", with no more detail. I'm no latin scholar; does it sound like latin?

OED is not available to me, but a book on my shelf (published 1989) quotes OED as saying "origin unknown". Is that still what OED says?

The same 1989 book references the cabalistic writings of Issac Luria (1534-72) listing the various angels (Gabriel, Michael, Raphael) and devils (Lilith, Belial, Azazel), and says that Abracadabra is the name of one of the devils. It suggests that this traces back to ancient cuneiform scripts.

Can anyone illuminate?