2. A class is simply a package that happens to provide methods to deal with object references.
3. A method is a function associated with a class or object. In other words: It's simply a subroutine that expects an object reference (or a package name, for class methods) as the first argument.
1. An object is simply a reference that happens to know which class it belongs to.
In other words: An object is a variable that belongs to a class.