When I was looking for a book for the Microcontroller I pronounced it as "Ar dwee noh" and the sales person knew exactly what I was talking about. Two weeks prior to me asking, I guess another customer was asking for the same thing, so in the Northwest US, we pronounce it "ar dwee noh".

I was just wondering about the same process, and I found this handy instructable on a solution you can use to etch infinitely. The solution is also very cheap to make, and has less environmental impact.

http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/