What is the term for a set of tables created via DDL operations that contains metadata about a database?

The appropriate term for a set of tables created through Data Definition Language (DDL) operations that contains metadata about a database is a data dictionary. A data dictionary holds information about the structure of the database including the names and types of tables, fields, relationships, and constraints. It serves as a centralized repository of information necessary for understanding the database's schema and can be used by database administrators and developers for documentation and for managing the database effectively.

In contrast, a data model refers to the conceptual framework or structure used to define the organization of data and its relationships but does not itself contain the actual metadata as a set of tables. A database is a collection of data organized in a way that allows for easy access and management, but it encompasses the data itself rather than just the metadata. A database management system (DBMS) is the software that interacts with end users, applications, and the database. While the DBMS manages the data, it is not specifically focused on the metadata structure that a data dictionary does. Thus, the data dictionary is a critical component within the broader context of databases and serves a distinct and essential role in managing metadata.