Structure
Glossaries contain the definition or description of a term. This not only includes the spelling, but also the semantics. An entry of a glossary also allows to add metadata and references to related terms and other information about the term.
A glossary does not need to be created in advance. It can be created on-the-fly. Whenever authors use a term that is part of the domain, the term is added to the glossary. If the term already exists the authors can make sure that it is used correctly and probably add additional information to the term's page in the glossary. If there are any problems encountered, the term should be discussed within the team.
A glossary may also help to create an ubiquitous language as demanded by the Domain Driven Design approach.