To create a new software system with GeneXus you must create a Knowledge Base (KB).
A Knowledge Base stores the Users' Views about the business reality to be modeled. Those User's Views are described in the Knowledge Base using Objects of many kinds.
The stored knowledge is structured information that is so pure and platform-independent, that GeneXus can make inferences to obtain more knowledge and also automatically generate the system (database and the application programs) in as many platforms you decide.
That is the reason behind a Knowledge Base is not just called ‘Project’ as used in common Software development jargon.