Words exist because of meaning. Once you’ve gotten the meaning, you can forget the words. Where can I find a man who has forgotten words so I can talk with him?
Chuang Tzu
In computer science and especially in artificial intelligence, ontologies play an important part in representing knowledge, usually about restricted parts of the real world. In knowledge management the representation and organization of knowledge is studied as well as the transfer of knowledge between systems and between agents. These areas are based on formal models for the representation of knowledge and the management and organization of knowledge has been studied in various contexts. When multi-agent systems are used, in order to communicate, the agents involved usually have to represent knowledge using an agreed knowledge model, otherwise there needs to be considerable effort in meaning negotiation (Avery & Yearwood, 2002). The purpose of these models is to facilitate effective communication between the agents or systems by providing a method for an unambiguous representation of the knowledge to be transferred. These restricted knowledge models for a specific domain are often called domain models.