Despite the ubiquity of the concept of sustainability, defining the term and construing meaning for different contexts is difficult. This paper presents several archetypes of sustainability that are useful for classifying and understanding existing definitions. Definitions that emphasize one part or another of the core concept of sustainability will be necessary at varying scales and in different contexts. This paper presents a conceptual guide that contrasts a dominant paradigm of economic growth and development with 'thick' and 'thin' versions of sustainability. Definitions of sustainability are explored in terms of their orientation to the ontology of nature, substitutability of resources, economic growth, population growth, role of technology, and social equity. (c) 2007 Society of Chemical Industry