Despite the overwhelming use of the metaphor ‘ecosystem’ in academia, industry, policy, and management, exact definitions of what ‘ecosystems’ really comprise are scarce and often inconsistent. Existing vague descriptions in the literature do not consider the boundaries of respective agglomerations, hence, they impede the evaluation of performance and outcome measures of respective ecosystems. This special issue is a first attempt to trace the ‘ecosystem’ discussion back to its roots—the ancient oikos, coined by the Greek philosopher Hesiod (700 BC), and aims to critically reflect on the usage of the term ‘ecosystem’, briefly summarize the extant literature and grasp the main features of entrepreneurial ecosystems, namely the economic, technological, and societal dimensions of entrepreneurial ecosystems. We intend to focus on the key elements that characterize an ecosystem, and hence, untangle under what conditions entrepreneurial firms shape and influence economic, technological, and societal thinking within their ecosystem.