How to Write a Glossary of Concepts

I think right now it's mostly reference. And i could see it expanding to include more narrative, or having a complimentary source of documentation later that covers that. One other memory from my past, a experience working on manuals, is how it feeds into product design. I found it incredibly help for sorting through these pretty abstract concepts. So i forced myself to pare down to set a fixed set of concepts and then went through and made sure i only ever used that one term.