Difference between folder and group in Xcode?

Question

In Xcode, what is the difference between a folder and a group? Are these interchangeable terms or is there a subtle difference?

Answer 1

A folder in Xcode represents a folder in the file system.

A group in Xcode is a "fake" folder which does NOT represent a folder in the file system.

It is common to use a combination of groups and folders for a given Xcode project.