Actor Definition

What is an actor? An actor is an entity that participates in a process, like a person, animal, plant, robot, application, organization, department, or system. An actor can be internal or external to the system, interacting with other entities.

For example, Students using a Campus Webshop are Actors and have the role of Shopper. Or, People ordering dinner in a Restaurant are Actors and have the role of Client.

When you model an actor, it is not common to model also the entity it embodies. Sometimes, it is wise to do so for the sake of understandability. If you model a process and use lanes, these lanes represent the roles that actors have.

The shape for the Actor is a wireframe person:

'Actor' has important relationships with 'Role' and 'Responsibility'.

Types of Actor

Common types of actor are:

• Business Actor
• Process Actor
• System Actor

Actors in Use Case Diagram

An actor has roles because of his position in a process. An actor is expected to perform certain tasks, which are the responsibilities of their roles.

Also Read

• Definition of Role
• Definition of Entity
• Definition of Responsibility

If you have comments or remarks about this Actor definition from Dragon1 or other terms, please email specs@dragon1.com.