The United States EPA (Environmental Protection Agency) states that the “traditional definition of sustainability calls for policies and strategies that meet society’s present needs without compromising the ability of future generations to meet their own needs.”
The definition provided by the EPA is great; however this definition is not universally used. Sustainability, as a buzz word, is more often than not abused.
Consider the community of Prairie Ridge. Prairie Ridge is advertised as “the Nation’s first Net-Zero Energy Community”. Net zero in this case refers to the communities’ energy-efficient homes. This is accomplished through a wide array of renewable energy including wind, solar photovoltaic panels and geothermal energy. This is a great accomplishment for Green Building and a case study in ways to take an otherwise conventional suburban neighborhood and sustain the energy that is consumed by the buildings.
What is not considered in the energy equation for Prairie Ridge is the high consumption of land with a single use. The land is consumed by 1/3 acre detached single-family lots 40 miles away from the heart of Chicago. The buildings may be sustainable, but how sustainable is the dependence on the automobile and gasoline?
I like to consider the words of Steve Mouzon and his book The Original Green. On The Original Green website, Steve states the following:
Originally, before the Thermostat Age, the places we built and buildings we built had no choice but to be green, otherwise people would freeze to death in the winter, die of heat strokes by summer, starve to death, or other really bad things would happen to them. Today, as we are working to re-learn how to live sustainably, much of the focus is on the gadgetry of green: Gizmo Green. This notion that we can simply invent more efficient mechanisms, and throw in some bamboo to boot, is only a small part of real sustainability.
Steve states that sustainable places must be built first. His four foundations of sustainable places are Nourishability, Accessibility, Serviceability and Securability. Beyond the context, Steve states that the buildings must then be Lovable, Durable, Flexible and Frugal. For more on this topic and the foundation’s of the Original Green, see Sustainability is More Than Gizmo Green.

The Triple Bottom Line is one method of measuring sustainability.

Other definitions of Sustainability involve the Triple Bottom Line, or the balance of People, Planet and Profit. Other variables of the tripod are Social, Environment and Economic and Patrick Geddes’ Folk, Work and Place.
In summary we should use the term, Sustainability, sparingly or at least clearly define the expectations when it is used. The definition of sustainability, unless stated with its use, is blurred and means different things to different people based on their experience with sustainability.