An operating system is system software that manages computer hardware, software resources, and provides common services for computer programs. Examples are; Windows, Linux, macOS, Android, iOS, Chrome OS, Free BSD
A desktop is the working area of a computer screen
The Start menu is the main gateway to your computer's programs, folders, and settings. It's called a menu because it provides a list of choices, just as a restaurant menu does. And as "Start" implies, it's often the place that you'll go to start or open things.
A tile is a type of shortcut on the Start Menu.
Addition Reference: Computing Textbook (Don Series) pg 19 - 25