OOP is an acronym for object-oriented programming which simply means that you are using an object-oriented language to create a program that contains one or more objects. On the other hand, OOD or object –oriented design is a design methodology used to plan object-oriented programs. OOD divides a problem into one or more objects. Anything that can be seen or touch is referred to as object. Every object has attributes and behaviours. The characteristics that describe the object are called attributes. It is also known as data or properties. The operations or actions that the object can either perform or have performed on it are called behaviours.

Another term in OOP is class. A class is a pattern or blueprint for creating an object. This contains all of the attributes and behaviour that describe the object. The object you create from a class is known as the instance of the class. Always remember that a class is not an object but an instance of the class is an object.