Package diagram

A package diagram[1] in the Unified Modeling Language depicts "specializations for Models and for Profiles that organize extensions to UML.

"[1] In addition to the standard UML Dependency relationship, there are two special types of dependencies defined between packages: A package import is "a directed relationship between an importing namespace and a package, indicating that the importing namespace adds the names of the members of the package to its own namespace.

In the current Unified Modeling Language 2.5.1 (December 2017), Package Merge is no longer used within the specification.

Package diagrams can use packages that represent the different layers of a software system to illustrate the layered architecture of a software system.

The dependencies between these packages can be adorned with labels / stereotypes to indicate the communication mechanism between the layers.