A business glossary consists of business terms that allow data consumers from different departments or lines of businesses in an organization to have a common understanding of data in their data estate. It helps to create a standard and consistency so that every user in an organization understands and communicates via the same business terminology.
However, each department or team would like to manage their own business terms as the same term name can be interpreted differently across various departments. For example - The Finance department in an organization may define a business term "Customer" as an individual or business that pays the organization for the goods or services delivered whereas the Sales department in the same organization may define the same term "Customer" as an individual or business who purchases goods or services from an organization.
In order to segregate business terms belonging to different areas in an organization Microsoft Purview now supports multiple business glossaries. Each glossary is a container for multiple business terms and can belong to a separate team, department, or line of business in your organization.
To learn more about Microsoft Purview multi glossary feature see our documentation here.