Herald means to announce or signal that something important is coming. When dark clouds herald a storm, they warn you that rain is on the way. When robins appear in your yard after a long winter, they herald spring. Scientists watching for the first signs of a volcanic eruption look for small earthquakes that might herald bigger activity.

The word comes from medieval times, when a herald was an official messenger who announced news for kings and nobles. A herald might proclaim the arrival of visiting royalty or read important declarations to crowds. In tournaments, heralds announced the knights before they competed.

Today we use herald more broadly for anything that signals what's ahead. A student yawning repeatedly might herald how boring they find a lecture. Your dog running to the door could herald your parents' arrival home. The first yellow leaf on a tree heralds autumn.

Herald can also be a noun: a person or thing that announces something. The rooster serves as a herald of dawn. A herald brings news of things to come, whether welcome or unwelcome.