I haven’t actually tried it myself, but you might look at wp-dokuwiki and see if that does what you need.
Or, possibly, the dw2wp plugin. It seems to let you import a browseable version of a dokuwiki, which might serve your needs better.
If you do try either of these, I’d love to hear the results!
Just use a full install of WordPress for this complete purpose. Each post is an “Entry” in your encylopedia. The post title is the Entry title (the word).
You can use alphabetical query, or plugins like WP-SNAP to display alphabatized indexes (Post Archives for all time, or by-category, A to Z)
In this way images are as easy as they can be with WP. And you can get fancy with Custom Fields to do all kinds of things for each entry.
While I’m sure that would work, it just seems to me that if I’m going to go to that much trouble, I might as well just install MediaWiki in a subdirectory. I mean, if I have to install something special, I might as well just use something that’s designed to do specifically what I want.
There are several threads about integrating MediaWiki with WordPress in various ways, but none of them seem any better than the plugins that have already been mentioned.
If anyone has any new ideas, though, I’d love to hear them!