This paper views a system as being made up of two sections: Domain and Port. It recognizes the need to distinguish the two sections as objects having differing characteristics and roles in a system. Focus is placed on understanding and identifying objects that characterize the Domain section of a system. The identification process differs from contemporary object-oriented development methods in that the three elements of data (static property), operations (dynamic property) and policies of an object are considered as important features of an object definition. The paper suggests that these features be specified early in the development process. Objects in the Port section and how they are inter-connected with objects in the Domain section will be briefly discussed. A more thorough discussion of Port section objects will be carried out in a separate paper.