Customizing the metamodel : Keywords for USRPROPS : INSTANTIABLE
  
INSTANTIABLE
The INSTANTIABLE keyword is used only with definitions. You can use this keyword to create an instance of a definition type.
Example
DEFINITION "EA Rule"
{
INSTANTIABLE
PROPERTY "Missions"{ EDIT HETEROGENEOUSLISTOF "EA Mission" AND_SUBTYPES ASGRID SHOW_ON_INSTANCES}
}
Note This keyword is not a property and can not be inherited. Subtypes of an instantiable type must also use this keyword if they are required to be instantiable.