"Big Apple" is a nickname for New York City. It was first popularized in the 1920s by John J. Fitz Gerald, a sports writer for the New York Morning Telegraph. Its popularity since the 1970s is due to a promotional campaign by the New York Convention and Visitors Bureau, known now as NYC & Company.
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.
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".
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.