#mail.aggregation__post  any particular collection of letters or packages that is delivered; "your mail is on the table"; "is there any post for me?"; "she was opening her post"
  subtype:  mailing.mail  mail sent by a sender at one time; "the candidate sent out three large mailings"
  supertype:  aggregation__collection__accumulation__assemblage  several things grouped together
     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 mail.aggregation; click here to add one.