In case you are unfamiliar with some of the terminology of modern object oriented programming (OOP), here are some plain English definitions and examples: "Class" - This is how "objects" are classified. - Each object belongs to a class or category. - There is a hierarchical arrangement of objects "methods" and other classes, under classes. "Object" - An object is a data structure that can "inherit" the properties of its parents. - Objects fall under classes. "Method" - A method is a function or procedure, which means it actually does something to something. - Methods also fall under classes. "Instance" - A unique copy of a "class" with all of its methods and objects. - A change in one instance does not affect other instances. "Event" - An event is when something happens in a GUI. - It can be a mouse movement, button click, etc. - Event handlers are "methods". Here is a Python example: MyClass: # A new class is defined. def my_method(self, my_number): # A new method is defined # with the parameter "my_number". self.my_object = number # A new object is defined. my_intance = MyClass() # An instance is made. my_instance.my_method(2) # The method is called. print my_instance.my_object # This will print "2". (Let me know if something is wrong here.)