In 1989, the World Commission on Environment and Development (Brundtland Commission) articulated what has now become a widely accepted definition of of the word Sustainability: "[to meet] the needs of the present without compromising the ability of future generations to meet their own needs.”
The word is much used these days. In the business context, it is often used as an alternative for Corporate Social Responsibility (CSR), or even interchangeably with Triple Bottom Line (TBL). In any case...