Business glossary

A business glossary is a controlled list of business terms, such as "active user," "churned customer," or "net revenue," each with one agreed definition, an owner, and notes on how it should and shouldn't be used. It exists independently of any database table, so the same definition can apply consistently across multiple systems.

This differs from a data dictionary, which documents the technical structure of specific tables and columns, and from a semantic layer, which turns glossary definitions into executable metric logic that BI tools can query directly. A well-run glossary typically feeds both: stewards agree the definition in the glossary, and engineers implement it once in the semantic layer, as part of broader metadata management.

Glossaries matter because ambiguous terminology is one of the most common sources of dashboards disagreeing with each other; two teams computing a KPI like "active user" with different windows will get different numbers and neither is technically wrong. Ownership of glossary terms is usually assigned through data stewardship, and reviewed under a broader data governance program. The common failure is writing definitions once and never revisiting them as the business changes, or letting teams silently maintain their own competing versions.