The cluster defined by Michael Porter

“Clusters are geographic concentrations of interconnected companies and institutions, in a given area. Clusters comprise a group of related industries and other entities important from the point of view of competition. These include, for example, suppliers of specialized inputs such as components, machinery and services, and providers of specialized infrastructure. Often extend downstream clusters to various distribution channels and customers and laterally to manufacturers of complementary products and the industries related by skills, technologies or common inputs. Finally, some clusters include governmental and other institutions – such as universities, standards agencies, think tanks, vocational training providers and employers – that provide specialized training, education, information, research and technical support ”
Michael Porter