Big Apple
"The Big Apple" was popularized as a name for New York City by John J. Fitz Gerald in a number of horse-racing articles for the "New York Morning Telegraph" in the 1920s. The earliest of these was a casual reference on 3rd May, 1921:
Big Apple
By the late 1920s, New York writers other than Fitz Gerald were starting to use "Big Apple" and were using it in contexts other than horse-racing. "The Big Apple" was a popular song and dance in the 1930s. Walter Winchell and other writers continued to use the term in the 1940s and 1950s, but by the 1960s it had generally come to be known as an old name for New York.