From Maria Popova:

On May 3, 1921, John J. Fitz Gerald — a sports journalist for the New York Morning Telegraph reporting on the horse-racing circuit — suddenly began referring to results from New York City as news from “the big apple.” He soon titled his entire column “Around the Big Apple,” extolling the Big Apple as “the dream of every lad that had ever thrown a leg over a thoroughbred and the goal of all horsemen.” Eventually, people began wondering why he had so nicknamed their city.

Five years after he first began using the term, Fitz Gerald half-answered.

Several years earlier, traveling to New Orleans for a race, he had overheard two African American stable hands discussing the horses in their respective care and where they were headed next. One of the young men told the other, in a “bright and snappy” quip, that the horse was going to “the big apple.” Fitz Gerald, knowing that the horse was in fact headed to New York City, seized on the term without asking where it came from — something about it just felt like the right poetic image for the grandeur and lushness of life in his hometown.

He died without ever saying anything else about it, having seeded into the urban dictionary the single most powerful and recognizable botanical metaphor in popular culture.

Popova goes further, tracing out the origins and meaning of the phrase “big apple.”

I’ve heard New York described as “The Big Apple” a billion times. Only in passing have I wondered where this phrase came from and how it became associated with New York City. Much of our vernacular we inherited or picked up, and the meaning and origin becomes lost to time.

“The Big Apple” is just one example. If you want another fun dive, check out this list of phrases that came from Shakespeare.