Merriam-Webster's Word of the Day for September 14, 2023 is:

harbinger • \HAHR-bun-jer\  • noun

A harbinger is something that foreshadows, or gives an early indication of, something that will happen in the future.

// When the star running back went down with an injury in the team’s first game, it turned out to be the harbinger of a disappointing season.

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Examples:

“Whether a subtle whiff of campfire on a cool autumn breeze or the less-than-subtle lure of a pumpkin spice latte, the spicy, savory harbingers of fall spark a shift in the food and wine we crave.” — Anna Lee Iijima, The Chicago Tribune, 14 Sept. 2022

Did you know?

In J. R. R. Tolkien's The Fellowship of the Ring, four hobbits—pursued by riders in black—seek safe harbor in the village of Bree. Unbeknownst to the hobbits, the innkeeper of The Prancing Pony, Butterbur, was made aware of their potential arrival by the wizard Gandalf some months prior (“... I was asked to look out for hobbits of the Shire ...”). When you consider the oldest, now-obsolete definitions of harbinger, there are multiple harbingers in this section of the tale. The first is Butterbur himself: coming from the Anglo-French herberge, meaning “lodgings,” harbinger was used as long ago as the 12th century to mean “one who provides lodgings.” Later on, harbinger was also used for a person sent ahead of a main party to seek lodgings. Those sent ahead would announce the approach of those following behind (the hobbits did not send Gandalf to Bree, but he did still herald their eventual arrival—making him a harbinger of sorts), which is how our modern sense of harbinger came to be used for someone or something which foretells a future event—such as how the hobbits’ arrival is a harbinger of the evil pursuing them and threatening all of Middle Earth.