A ‘Generalised Entity Model’ is a data model that represents things, like Organisations and People that actually exist in the real-world, as Entities and ALL the Relationships between them.

It also recognises that some information, like Address and Photos, for example are needed for more than one 'Entity Type'.  So has only one method of storing each type of information.  This simplies the system as there is only one way of doing the same thing.  It also makes it easy for the developers to add more advanced features, as once done it will work throughout the system the same way and they are never going to have to do it again!

It also never duplicates data for anything! If something exists only once in the real-world, then there is only one copy of the data in the system. So for things like Phone Numbers and Addresses, for example, the system does not duplicate the data between people that have the same Address. It stores each unique address once and simply remembers who uses that Address.  So if you change the details of the Address it automatically changes for everyone that uses it.