The word "harbinger" refers to something or someone that announces or signals the approach of another. It is often used to denote signs or indicators that foreshadow future events or developments. For example, a certain bird might be a harbinger of spring, suggesting that warmer weather is coming.
The word "harbinger" comes from the Old French term "herbergeor," which means "one that provides lodging." It was derived from "herberge," meaning "a lodging." The transition in meaning reflects the idea of someone who comes ahead to announce the arrival of others, much like a host prepares the way for guests.