How do I create a Sharepoint glossary without using an app?

Hi AMJ_Devon ,

the simplest way to do this is a just a Custom List where you add a Multiple Lines of Text field called 'Defintion' . All lists have a built in search box and users can filter/sort based on the Title. you could also add another Choice (dropdown) field called 'Category' and categorize each entry. This would allow users to sort by another column and you could group your entries in a way that may be more intuitive than simply alphabetical. 

You can also create custom views where the results are refined to Titles that start with a certain letter. SharePoint will build the list of views for you so you don't need to manually add the links to the views on a page.

Hope this helps. Happy to jump on a private message thread if you want help with this.