In the context of databases, a database domain refers to the definition of permissible values that a particular attribute can take in a database table or relation. It specifies the data type and constraints that can be applied to the attribute. The domain defines the set of valid values for the attribute, ensuring data integrity and consistency within the database. For example, a database domain for the "Age" attribute in a "Person" table might be defined as an integer data type with constraints that enforce that the age must be a positive number within a specific range (e.g., 1 to 120). This domain definition ensures that only valid and acceptable values are allowed for the "Age" attribute in the "Person" table. If any attempt is made to insert or update data violating this domain definition, the database management system will reject the operation, maintaining the integrity of the data.