Hi Annie,
First of all, when you post to these forums you have to be patient. Although Moodle is a very active community (of volunteers), you cannot expect a question to be answered within 24 hours.
There are 2 ways to solve your problem. But the solution also depends on how your students will be using your global glossary.
Do you want:
a. the students to be able to browse that glossary? add to it? etc.
b. or do you only want that words in your moodle site's courses will be automatically linked to their definitions in that glossary?
If (b), then remember that a global does not have to be created on your moodle site's front page to be accessible from all its courses. Just create a special course (name it e.g. "Glossary Course") and make it Global (in its settings).
If (a), then change the front page global glossary's permissions, to deny its viewing from guests.
Joseph