Simple Definition:

Sustainable development is the concept of meeting the needs of the present generation without compromising the ability of future generations to meet their own needs. It involves finding ways to use resources responsibly and preserve the environment for the long term. For example, sustainable development could mean using renewable energy sources, like solar or wind power, instead of relying on nonrenewable resources like coal or oil.

Very Simple Definition:

Sustainable development means finding ways to meet our needs without hurting the Earth for the future. It’s about using things wisely and making sure we can keep on using them. For example, it could mean using the sun and wind for power instead of things that run out, like oil or coal.