#subsystem  a system that is part of some larger system
  supertype:  system  a group of independent but interrelated elements comprising a unified whole; "a vast system of production and distribution and consumption keep the country going"
     supertype:  group__grouping  any number of entities (members) considered as a unit
        supertype:  collection  something gathering separated things (entities/situations)
           supertype:  divisible_entity__divisibleentity  many classifications under this category are application-dependant
              supertype:  entity  something that can be "involved" in a situation
                 supertype:  thing__something___T__t___3D_or_4D_thing_or_anything_else  any category (type or individual) is instance of this type; any type is also a subtype of this type
              supertype:  divisible_thing__divisiblething
                 supertype:  thing__something___T__t___3D_or_4D_thing_or_anything_else  any category (type or individual) is instance of this type; any type is also a subtype of this type

No statement uses or specializes subsystem; click here to add one.