European Project Definitions
The CIPRNet project  uses the following definition:
The DIESIS project  gives the following definition:
It features a number of autonomous “agents” which are each programmed to make decisions according to certain pre-defined rules. The resulting interactions can give rise to emergent patterns that might not have been obvious when considering each of the agents in isolation. Agents can be animate or inanimate, e.g., people, financial institutions, or the environment.