Posterity means all the people who will live after you: future generations who inherit the world you help create. When the Founding Fathers wrote that they were securing “the blessings of liberty to ourselves and our posterity,” they meant for themselves, their children, grandchildren, and Americans centuries into the future.

The word captures something important: the choices we make today affect people we'll never meet. When a town plants trees along Main Street, they're thinking of posterity. Those trees might take fifty years to provide real shade, but the people who planted them knew future generations would enjoy sitting beneath them. When scientists preserve ancient artifacts in museums, or when conservationists protect forests and wildlife, they're working for posterity.

You might hear someone say they're doing something “for posterity,” meaning they want it to last or be remembered long after they're gone. Photographs preserve memories for posterity. Great books, inventions, and institutions endure for posterity. In this way, posterity reminds us that we're part of a long chain: we inherited much from those who came before us, and we'll pass something forward to those who come after.