Critical Description
The properties Relation and Domain seem to have the same responsibility. Relations could be designed hierarchically and therefore cover the domain aspect. This is especially true since the domain and relation are non-overlapping.
The type property also handles a second dimension to the categorization.
The problem with the domain property is the missing domain doctype. This way it requires work to provide a domain view on the glossary. We would need to add a domain doctype, but this would make the use of the glossary / core doctypes more complicated.
Therefore we remove the Domain property to make using the glossary item doctype easier.
