When you preview a course or view a published course, there are a couple ways to view the definition of a term in the glossary.
Terms with glossary definitions display with an underline on the page.
When you roll your cursor over the term, a yellow highlight appears over the word and the definition displays.
You can click the term and a pop-up displays the definition. There is also a link to open the entire glossary, where you can see the list of all terms and definitions in the course. Close the pop-up window when you're done.