A Package is a grouping element that acts as a container for other modeling elements (including other Packages) and diagrams; Packages are represented in the Project Browser as a familiar folder icon. Using the Package element, hierarchical models can be constructed allowing complex systems to be decomposed and categorized. Packages and their contents can be moved around freely in the Project Browser, so that you can easily refactor the repository. They can be copied and pasted between model branches, renamed or viewed as a list. Packages are important in Enterprise Architect because a number of functions can be applied at Package level, such as Baselines, Version Control, Transformation and more.
Formally, the Package is a Namespace for the members it contains, and a model element can be a member of one and only one Package. In software engineering and other formal modeling disciplines a Package can be set as a Namespace Root, which acts as the starting point of a given namespace.