A formal structure for a defined population, whose finance, management, scope, and content is defined by law and regulations.
It provides for services to be delivered to people to contribute to their health…delivered in defined settings, such as homes, educational institutions, workplaces, public places, communities, hospitals, and clinics.

A health system consists of all organizations, people, and actions whose primary intent is to promote, restore, or maintain health. This includes efforts to influence determinants of health as well as more direct health-improving activities.
It is therefore more than the pyramid of publicly owned facilities that deliver personal health services. It includes, for example, a mother caring for a sick child at home; private providers; behavior change programs; vector-control campaigns; health insurance organizations; and occupational health and safety legislation. It includes inter-sectoral action by health staff, for example, encouraging the ministry of education to promote female education, a well known determinant of better health.

World Health Organization. European Observatory on Health Systems and Policies. Glossary. 2009.