Definition
Sustainability, otherwise known as sustainable development, is defined by the UN World Commission on Environment and Development to be "development that meets the needs of present users without compromising the ability of future generations to meet their own needs."
In order to fully understand what this means, it can be helpful to apply this principle of sustainable development into the contexts of the three pillars of sustainability: social, environment, and economic. In order for sustainable development to be effective, one must find solutions that are ecologically sound, socially equitable, and economically viable. Learn more about the history the three pillars in Purvis, Mao, and Robinson's 2017 open access article.
Citation:
Purvis, B., Mao, Y. & Robinson, D (2019). Three pillars of sustainability: in search of conceptual origins. Sustain Sci. 14, 681–695 https://doi.org/10.1007/s11625-018-0627-5
World Commission on Environment and Development. (1987). Our common future. Oxford: Oxford University Press. https://sustainabledevelopment.un.org/content/documents/5987our-common-future.pdf