Big apple-the most likely explanation is:1920s era jazz musicians picked it up from stable guys and horseracing people from new orleans who considered ny races and ny gigs to be where the money was. so since a horse, up for a big purse in the nyc, cant get paid off in big money himself, the lingo promised him a big apple. so playing ny and getting on record dates here became known as the big apple for musicians too. a sports writer in those days, john fitzpatrick, picked up on the lingo and called his column around the big apple. if you go to 54th and broadway you will see that he was recognized by the city by renaming the corner where he lived, big apple corner. there was a club called the big apple on the corner of 135th and 7th ave (across the street from smalls paradise). the corner is marked by a whimsical display of an upside-down apple announcing the location. see these sites and more on a big apple jazz tour.