Although the history of Big Apple was once thought a mystery, research – primarily by amateur etymologist Barry Popik and Gerald Cohen of Missouri University of Science and Technology – has provided a reasonably clear picture of the term's history. Previously, there were a number of false etymologies, including a claim that the term derived from a New York brothel whose madam was known as Eve. This was subsequently exposed as a hoax and has been replaced on the source website with more accurate information.
The earliest citation for "big apple" is the 1909 book The Wayfarer in New York by Edward S. Martin, writing: "Kansas is apt to see in New York a greedy city.... It inclines to think that the big apple gets a disproportionate share of the national sap" (emphasis added). William Safire considered this the coinage, but the Random House Dictionary of American Slang considers the usage "metaphorical or perhaps proverbial, rather than a concrete example of the later slang term", and Popik likewise does not consider this the coinage.
In the early 1920s, "apple" was used in reference to the many racing courses in and around New York City. Apple referred to the prizes being awarded for the races – as these were important races, the rewards were substantial.
The Big Apple was first popularized as a reference to New York City by John J. Fitz Gerald in a number of New York Morning Telegraph articles in the 1920s in reference to New York horse-racing. The earliest of these was a casual reference on May 3, 1921:
J. P. Smith, with Tippity Witchet and others of the L. T. Bauer string, is scheduled to start for "the big apple" to-morrow after a most prosperous Spring campaign at Bowie and Havre de Grace.
Fitz Gerald referred to the "big apple" frequently thereafter. He explained his use in a February 18, 1924, column under the headline "Around the Big Apple":
The Big Apple. The dream of every lad that ever threw a leg over a thoroughbred and the goal of all horsemen. There's only one Big Apple. That's New York.
Two dusky stable hands were leading a pair of thoroughbreds around the "cooling rings" of adjoining stables at the Fair Grounds in New Orleans and engaging in desultory conversation.
"Where y'all goin' from here?" queried one.
"From here we're headin' for The Big Apple," proudly replied the other.
"Well, you'd better fatten up them skinners or all you'll get from the apple will be the core," was the quick rejoinder.
Fitz Gerald's reference to the "dusky" stable hands suggests the term's origin may lie in African-American culture. Support for this is found in the Chicago Defender, an African-American newspaper that had a national circulation. “Ragtime” Billy Tucker, a vaudeville/ragtime performer and writer for the Defender, there used "big apple" to refer to New York in a non-horse-racing context on September 16, 1922:
I trust your trip to 'the big apple' (New York) was a huge success and only wish that I had been able to make it with you.
Tucker had earlier used "Big Apple" as a reference to a different city, Los Angeles. This example, from May 15, 1920, is the earliest known use of "Big Apple" to refer to any city. It is possible that the writer simply understood "Big Apple" as an appropriate nickname for any large city:
Dear Pal, Tony: No, Ragtime Billy Tucker hasn't dropped completely out of existence, but is still in the 'Big Apple', Los Angeles.