First off, this is a HUGE miss in still not existing as a feature. EVERYONE would start using it immediately, and many happy people would raise a toast to Rise if it was simply ADDED TO THE TOOL (the manner in which you prioritize your roadmap and feature requests is still a mystery on the level of quantum entanglement, as far as I'm concerned).
Secondly, what I'm planning on doing for an upcoming course is to make the glossary as the FIRST lesson, and not make it required to view each individual term (I have 96 of them) in order to move on. And then each subsequent lesson I'll build as requiring completion before they can continue. This way, if a user jumps to the glossary (either via a link or a button) they are jumping BACKWARDS in the course, and then they can always return to their spot by simply moving ahead as far as the course allows, So, for example, if a learner is on lesson 5 of 9, and needs to see the definition of Quantum Entanglement, they can jump back to the first lesson, read the definition, and then use the left hand navigation to return to lesson 5, which is as far as the course will let them, as they haven't completed lessons 6-9.
Hope that helps someone!