Any operating definition of "sustainability" should be useful across doctrine boundaries including, but not limited to: science, psychology, business, economics, entrepreneurship and politics. And rather than having specific or "new" meaning such as the meaning derived from the term "sustainable development" from the United Nations beginning in the late '80s, requiring long and difficult to remember explanation, the best operating definition is that which holds the broadest, simplest, easiest to understand, most teachable, most memorable and easy to communicate meaning for the most stakeholders. Furthermore, the operating definition must hold its water in any critical debate in diverse forums.  For example, the definition of "sustainability" can simply be "survival", meaning both long-term and short-term survival, encompassing the realms of ecology, human systems, organizational systems, local and regional community systems and economies. If something, anything, is not sustainable, i.e., it is not maintainable, it does not survive.