create a Glossary App

Same reflection as Rod: what about the learning interaction?  I could understand you don't use it if you need it for another language than English. Reason: you cannot use any combination character which you have in many languages. Example: ñ in mañana (Spanish), é in prévoir (French), ê in zeeën (Dutch)....

Any reason why you have not opted to use the Glossary Learning Interaction that ships with Captivate?

That allows for hundreds of entries, has search built in, and you can even upload your entries from an XML file to update the glossary within secconds.

You could add a text entry box to your slide and a multi-state object containing all the possible words and there definitions. When a user types in a word and presses submit you could change the multi-state object to show the definition. You would need to write an advanced action on the submit of your text entry box to check the value of what the learner has typed against the words that you wish to include. You would need one decision tab for each word. It might look something like this...

Obviously this could get rather large if you have 30, 40, 50 or more words in your glossary. You might want to reconsider having users type what they are looking for and merely have a list where they can click on each word to display the definitions. Might be easier in the long run.