Dopplebock Belgian Dubble and Triple
These are styles of beer. The double or triple or even quadruple (in the various languages) usually refer to stronger styles of beer. I have seen references to techniques that may double or triple something to create these styles but that does not seem to be the norm. Rather these are usually just brewed to a higher OG than similar styles.
I'm making a doppelbock right now. It's only my first home brew, so I don't know how much help I can be, but I do know a lot about the doppelbock in general and I can tell you what I've experienced so far.