What is Sustainability?

I was a little unclear about the exact definition of sustainability, so I looked it up on wikipedia. Wikipedia explained that "the essential aim of sustainable design is to produce places, products and services in a way that reduces the use of non-renewable resources, minimizes environment impact, and relates people with the natural environment". It also explains that this has just recently become more important in design within the last few years. We are becoming more aware of the impact we are having on the world, with our recent acceptance of global warming.