I've been in the same situation, Nixda :)
We use Confluence here, but only for monolingual content, like our knowledge-base, FAQs, etc. IMO, it's absolutely useless for managing bilingual content. If the product documentation needs to be available in multiple languages, then you really need a content management system (CMS) that actually designed for that job.
As penguin and others have said, a translation memory system (TMS) offers much more than just a glossary, particularly if particular phrases appear again and again, which is often the case with technical documentation. If cost is a factor (it certainly was for my employer), you could try OmegaT, an open-source TMS, that, as near as I can tell, has almost all of the features of Trados. That's what we went for, and I'm quite happy with it. There's plenty of depth to the program if you want to get really technical, and the community is quite helpful.
If you really just want a DE/EN glossary and want to stick to MS products, then I'd recommend using Access over tables in Word or Excel.