Basic OO Terms

Abstraction

The process of separating ideas from specific instances of those ideas at work.

Polymorphism

The provision of a single interface to entities of different types. Subtyping.

Inheritance

When an object or class is based on another object or class, using the same implementation; it is a mechanism for code reuse. The relationships of objects or classes through inheritance give rise to a hierarchy.

Encapsulation

Enclosing objects in a common interface in a way that makes them interchangeable, and guards their states from invalid changes