[rkomar]

I don't think that epubs are a good fit with dictionaries. They don't differentiate between any of the contents, making searching more difficult (you'll be searching the definitions as well as the words being defined). Generally, electronic dictionaries are created using some specific structure that a dictionary application understands (e.g. xdxf or sdict markup). You would probably be better off creating such a structured dictionary, and then converting that into whatever format is needed by your device.

I had a similar problem with a 1600 page dictionary I scanned for personal use. I created a PDF file of the scanned images, and used PDFMARKs to create an index for the dictionary. At the top level, I had a bookmark for each letter of the alphabet. Next level down, I grouped eight pages together, labeling them with the first and last word in each grouping. At the final level, I had a bookmark for each page, labeling it with the first and last word on that page. That way, I could find the location for each word with three clicks through the index. Obviously, that's a lot of work (almost 1800 bookmarks in my case), but it is worth it if the dictionary is used extensively afterwards.

If you insist on epub, maybe you can divide the contents in a similar way that would make navigation easier.