What is the purpose of the 'dictionary' - if its for spell checking then that's a feature of the calibre editor, and it has provision for custom dictionaries (which are essentially word lists).
If its something like
this then you could include it in the book, probably at the back, either in the original text, or by adding it with the editor. And maybe you
could link occurrences of the 'words' in the text to the glossary entry.
I believe some e-readers incorporate on-board dictionaries (highlight a word and look it up), but I'm not sure if any provide for book specific custom dictionaries, and even if they did they'd all do it differently.
BR