In Mac/iOS programming, what is a "Foundation Object"?

Question

I've seen reference to "Foundation Object" (specifically in the NSJSONSerialization Class docs https://developer.apple.com/library/ios/documentation/foundation/reference/nsjsonserialization_class/Reference/Reference.html), however I'm not really sure what a "Foundation Object" is, and is it different than a "Core Foundation Object"?

Answer 1

It tells you in that link bout 3 lines further down.

The objects can be instances of...

• NSArray
• NSDictionary
• NSNumber
• NSDate
• NSString or
• NSNull