A role is a repository object that enables flexibility and simplicity in assigning access controls and identifying changing groups of users.
A role collects multiple capabilities into a single object that can be attached to an object and be associated with users and groups. The role defines the permissions. Instances of a role are attached to objects in the repository and those role group instances identify the audience that enjoys those permissions on the associated object.
Members of a role group specified on an object can participate in workflow tasks associated with that object.