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
The term "big apple" was used by Frank Sinatra in conversation with opera singer Dorothy Kirsten on an episode of the NBC radio program "Light Up Time" on March 28, 1950.