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:
List of nicknames of New York City
New York City is frequently shortened to simply "New York", "NY", or "NYC". New York City is also known as "The City" or "The Big City" in much of the eastern United States. Other monikers have the form of "Baghdad on the Subway" or "Hong Kong on the Hudson," a reference in different cases to the city's prominence or its immigrant groups.