Sustainability means using resources in a way that meets our needs today without making life harder for people in the future. When something is sustainable, it can continue indefinitely without running out or causing lasting damage.

Think of a forest where trees are carefully harvested: if loggers cut down only a few trees each year and plant new ones to replace them, the forest can provide wood for a very long time. That's sustainable forestry. But if they clear-cut every tree without replanting, the forest disappears and future generations get nothing. That's unsustainable.

The concept applies to many areas of life. A business practices sustainability when it makes profits without polluting rivers or exhausting natural resources. A farmer practices sustainability by rotating crops and maintaining healthy soil rather than depleting it. Even your allowance teaches sustainability: if you spend every penny immediately, you'll have nothing left for next week.

The word comes from the idea of something being able to sustain itself, to keep going under its own power. When engineers design sustainable buildings, they include features like solar panels and rainwater collection so the building requires fewer outside resources. When communities focus on sustainability, they're thinking about how their choices today affect the world their children and grandchildren will inherit.

Something sustainable doesn't just work for now. It works for the long haul, balancing present needs with future possibilities.