I'm actually going to answer this as I did not find any concrete solutions.
You have 2 options here:
Download and install Media Wiki on a sub-domain. It's a standalone system which looks exactly like Wikipedia.
Use an FAQ extension, such as Freestyle FAQs. More extensions can be found under the FAQ category on the Joomla Extensions Directory.
Don't use an extension or standalone system at all, but instead make full use of Joomla articles. You can create a category, tags and have you own menu items dedicated to your Wiki content. It will take a little longer to setup than an FAQ extension probably, however it means you don't add unnecessary bulk to your site.