A Dictionary is a specialized folder that allows the developer to organize classes, primitives, and interfaces for easy reuse.

Dictionaries that are defined within a segment can be used to define data types for use in that segment only. Dictionaries defined directly under the Model can be used to share data type definitions across multiple segments.

In general, items can be added to multiple dictionaries. However, if the IsUnique property of the Dictionary is set to True, then items can exist only in that Dictionary and cannot be included in other Dictionaries.