A knell is the slow, solemn sound of a bell ringing, especially at a funeral or to mark someone's death. The heavy, mournful tones of a church bell tolling one strike at a time create a knell that echoes across a town, announcing sad news.

The word comes from an old tradition: for centuries, church bells would ring in a particular slow pattern when someone died, alerting the community to gather and mourn together. That distinctive, somber ringing became known as a death knell.

Today, we also use “death knell” as a metaphor for anything that signals the end of something. When a beloved bookstore closes its doors for the last time, people might say it sounds the death knell for independent bookshops in their town. When a sports team loses its star player to injury, commentators might declare it the death knell of their championship hopes. In these cases, we're not talking about actual bells or death, but about clear signs that something important is ending or failing.

The word carries a sense of finality and sadness. A knell doesn't suggest hope or revival; it marks an ending that can't be undone.