I like the following definition or description of the word, which comes from Wikipedia:
The name sustainability is derived from the Latin sustinere (tenere, to hold; sub, up). Sustain can mean “maintain", "support", or "endure”. Since the 1980s sustainability has been used more in the sense of human sustainability on planet Earth and this has resulted in the most widely quoted definition of sustainability as a part of the concept sustainable development, that of the Brundtland Commission of the United Nations on March 20, 1987: “sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”
Unfortunately, I often hear and see the word being used very differently. One example is in the expression “sustainable growth” when it is being used to mean “sustained growth” or, in effect, “continued growth at the same sustained rate”. This is often the interpretation put on the word in the context of narratives about economic recovery after a recession, aka “returning to growth”. In such circumstances, the question we often hear is “is it sustainable?”, meaning “can the growth be sustained?”
Words are important, especially when their meaning can be misinterpreted. I try to make my use of the word “sustainability” clear, without coming across as being pedantic. I don’t always succeed.
The Planetary CFO - working towards a sustainable World Balance Sheet.