An Activity is a Class_of_physical_individual that indicates the nature of a process of transformation of an individual product during a period of time.
An Activity can be a specification for the process of transformation of an individual product during a period of time.
EXAMPLE - 'Part type XYZ_123 start up' is an Activity. Many periods of time in the life of an individual part of type XYZ_123 can be members of this Activity.
EXPRESS specification:
*) ENTITY Activity SUBTYPE OF (Class_of_physical_individual); END_ENTITY; (*