Thank you for the suggestion Sakshi> I ended up doing the following to add a category called "TV production" to all 500+ words in the glossary.
1- Created a category called "TV Production".
2- Edited one of the entries so it would be under the newly created category.
3- Exported the entire glossary to an xml file
4- Opened the xml file and used the find and replace function on Notepad++ to find the close entry tag and replace with the category and the closing entry tag like so:
FInd:
</ENTRY>
Replace with:
<CATEGORIES>
<CATEGORY>
<NAME>Television Production</NAME>
</CATEGORY>
</CATEGORIES>
</ENTRY>
5- Then I uploaded the XML file to a new glossary and done.