Polymorphism refers to a function having the same name but being used in different ways and different scenarios, making programming easier and more intuitive. Polymorphism is a fundamental concept in object-oriented programming that allows one function to display multiple functionalities through inheritance, where a child class inherits all methods from the parent class. In Python, polymorphism can be implemented through classes having different methods with the same name, inheritance where child classes can override parent methods, and by defining functions that can accept different object types.