Architecting and designing : UML 2.0 Lite : UML models : UML class diagrams : Class stereotype
  
Class stereotype
A class stereotype is a modeling element that extends the notion of a class. Certain modeling elements that exhibit behavior that is close to a class can be described as a class with a stereotype. For example, a class utility, which is a grouping of behavior (methods), can be described as a class with stereotype utility. Select one of the predefined stereotypes in the Stereotype property of the class definition, or type a new stereotype in the Stereotype list box.
An actor is a special stereotype of a class. A class with stereotype of actor is drawn differently than a simple class. The actor class is pictured as a stick figure.
See also
UML class diagrams