I could argue that all database management systems (DBMS) have a thing called data dictionary. It is a set of views or tables that provide access to metadata about database schema - list of tables, columns, keys, etc. They are located in special system schema or are available implicitly in all schemas.
SQL-92 standard (for relational / SQL databases) specifies data dictionary called information schema. This standard defines tables data dictionary provides ..
Most popular databases provide also their proprietary data dictionary, often referred to as System Catalog (or system views, system tables or simply catalog).