This part of IEC 62656 specifies the logical structure for a set of spreadsheets, used as "data parcels", to define, transfer and register product ontologies. Such ontology descriptions in other literatures or disciplines are sometimes called "reference dictionaries". Thus the logical data structure described in this standard is named "Parcellized Ontology Model" or "POM" for short, and each vehicle of transport of the model is called a "parcel", and may be used for definition, transfer, and registering of a reference dictionary as a collection of metadata, or for similar purposes for instances belonging to a certain class of the reference dictionary. Moreover, this ontology model allows for modelling or modifying an ontology model per se as a set of instance data, thus it enables an ontology model to evolve over time.