Hi Julie,
You can upload an .xml file. I think the best way to do it would be to create a small Glossary first and export it to get the format. You could probably use an xml editor then to create a bigger file and then upload.
There's some guidance here:
https://help.totaralearning.com/display/TH14/Glossary
https://en.wikipedia.org/wiki/Comparison_of_XML_editors
You can make any new entries subject to approval by a Trainer, and/or set a comprehensive list of capabilities in the module which includes Create new entries mod/glossary:write
cheers,
George.