What is inheritance?

Inheritance - is the concept of passing the traits of a class to another class.

A class comprises of a collection of types of encapsulated instance variables and types of methods, events, properties, possibly with implementation of those types together with a constructor function that can be used to create objects of the class. A class is a cohesive package that comprises of a particular kind of compile-time metadata. A Class describes the rules by which objects behave; these objects are referred to as "instances" of that class. (Reference)

Classes can inherit from another class. This is accomplished by putting a colon after the class name when declaring the class, and naming the class to inherit from—the base class—after the colon. (Reference)