The definition of risk is fundamental for the proper understanding, assessment, characterization, perception, communication and handling of risk. There are, however, many definitions and perspectives on risk, and there is a continuous debate on how the risk concept should be defined and interpreted. In this webinar, Terje Aven and Roger Flage will give a historical perspective on the development of the risk concept. Focus will be on professional settings. Some reflections on future developments will also be provided, covering both theory and practice.