A herald is a sign of things to come. A chilly day in October is a herald of the coming winter.
Years ago, a herald was an official who announced important news to the people. This is why many newspapers today have herald in their name. Nowadays, the noun herald refers to an early indicator that something is about to happen. Herald can also be used as a verb meaning "to praise" or "to greet enthusiastically." If you've been away from home for a long time, your family might herald your return, especially if you come bearing gifts.