What does the NS prefix mean?

Question

Many classes in Cocoa/Cocoa Touch have the NS prefix. What does it mean?

Answer 1

It is the NextStep (= NS) heritage. NeXT was the computer company that Steve Jobs formed after he quit Apple in 1985, and NextStep was it's operating system (UNIX based) together with the Obj-C language and runtime. Together with it's libraries and tools, NextStep was later renamed OpenStep (which was also the name on an API that NeXT developed together with Sun), which in turn later became Cocoa.

These different names are actually quite confusing (especially since some of the names differs only in which characters are upper or lower case..), try this for an explanation:

TheMerger OpenstepConfusion