centenary

The word "centenary" comes from Latin centenarius (“of a hundred”), from centum (“one hundred”), and it most often refers to a 100th anniversary (or the celebration of it). It's more than just saying something is "100 years old"; it specifically marks the completion of a century. While we often use "anniversary" for any yearly remembrance, "centenary" carries a weight of historical significance. Less commonly, it can also refer to a 100-year span.

You might read about a university celebrating its centenary—marking 100 years since its founding—or perhaps a town commemorating the centenary of a pivotal battle fought on its land. It's used to denote an event or institution that has endured for a full century, demonstrating resilience and lasting impact.

The term isn't limited to events in the past, either. You might hear about plans looking toward a future centenary—for example, an organization planning now for how it will commemorate the centenary of the 1964 Tokyo Olympics in 2064. It implies a long-term perspective and a recognition of an enduring legacy.

One quick note on usage: in American English, centennial is often more common, but centenary is widely used (especially in British and Commonwealth English) and is readily understood.

So, when you encounter "centenary," think beyond just "100 years." Think about a landmark achievement, a significant milestone, and a celebration of something that has stood the test of time—or is poised to do so.