why is ny city called the big apple??

Answer 1

During the height of the jazz area in the early 1950s, jazz musicians used to play on 52nd Street, then known as the street with all the jazz clubs. Being hipsters, the musicians were talking one night after playing and one referred NYC as the Big Apple. Other musicians thought that was a cool name for NYC and started to call it the "Big Apple." And the name caught on with others outside of the jazz circle and NYC has been known as the "Big Apple" ever since.

Answer 2

because people like to eat big apple there!!
actually, i dunno, but this might help:

http://www.salwen.com/apple.html