Architecting and designing : SysML : Model Elements : Classifiers : Actor
  
Actor
An Actor specifies a role played by a user or any other system that interacts with the subject.
Actors may represent roles played by human users, external hardware, or other subjects.
Example
A person may have a job title of Developer.
When that person is performing an activity such as training users on use of the product, the person is playing the role of Trainer.
When that person is performing an activity such as demonstrating the product at a trade show, they are playing the role of Technical Seller.
When that person is developing the product, they are performing the role of Developer.
See also
Activity
Association
DataType
Enumeration
Extension
FunctionBehavior
Information Item
Interaction
Interface
Opaque Behavior
Primitive Type
Signal
State Machine
Stereotype
Use Case
Go up to
Classifiers