There are three principles of OOP short definations

Encapsulation
Inheritance
Polymorphism

Encapsulation is the mechanism that binds together code and the data it manipulates and keeps both safe from outside interference and misuse. 

Inheritance is the process by which one object acquires the properties of another object. By use of inheritance, an object would need only to define those qualities that make it unique within its class. It can inherit its general attributes from its parent. Thus, it is the inheritance mechanism that makes it possible for one object to be a specific instance of a more general case.

Polymorphism is a feature that allows one interface to be used for a general class of actions. The specific action is determined by the exact nature of the situation.