[piperswe]

Cocoa is the user interface toolkit used by macOS and iOS applications alike (though on iOS it's called Cocoa Touch). Swift is a programming languages that's often used to write Cocoa applications, usually through the AppKit, UIKit, or SwiftUI frameworks.

[Wowfunhappy]

I'll add that I think GP is confusing Cocoa with Objective-C. Swift does replace Objective-C.