According to the World Commission on Environment and Development, sustainability and its development is defined as the "development that meets the needs of the present without jeopardizing the ability of future generations to meet their own needs". This definition is hard to grasp in our current environment of what Herman Daly calls "Growthmania", in where needs have been replaced by wants. Therefore, our perception of what we need now may differ to what future generations may need.
According to the New York Times article written by Andrew Zolli, we should be focusing our attention on "resiliency". Yet he fails to see that resiliency is just part of sustainability. If something is sustainable, it must then be resilient and vice versa. This misinterpretation of sustainability must have been caused by the previous definition.
This definition is also derived from a purely humanitarian point of view in where the human race is the epicenter. Within this, the environment only plays a secondary role in providing us the means to meet our needs and nothing more. Therefore, we can ignore the other aspects of nature than we don't perceive as "useful".
In terms of defining sustainability, I myself lean towards ecological equilibrium as mentioned by Donella Meadows. When a system is in equilibrium, there is an equal balance of input and output. What we take from the environment, we have to give back in the same amount. This limits our capacity to grow but rightfully so. Limits exist throughout nature and we are not beyond that. These limits ensure our survival as a species because what we have now will be maintained for generations to come. However, I don't think that definition of sustainability can be used at our current state. It has to be more now. We have taken too much from the environment.
There is a new genre of architecture that I believe surpasses previous sustainable design called "regenerative" architecture. It is buildings that give back more to the environment than what it takes from it. Within this discipline, a new definition of sustainability can be found. Ecological equilibrium must be met but only until we give back to the environment for generations of environmental abuse.