What is an intelligent system?

The term intelligent system has emerged in the field of information technology as a category of computer systems derived from successful applications of artificial intelligence. This paper proposes a general description that identifies the main properties and types of components typically found in such systems. Adopting an integrative and pedagogical approach, this description provides a conceptual framework for systems engineering practitioners seeking a coherent vocabulary and organizational structure to approach the analysis and construction of intelligent systems. The paper presents examples of both classical and modern intelligent systems to illustrate the generality and applicability of the description.