emotional result we call happiness, most of us tend to engage in behaviour that is the exact opposite and then feel awful and inadequate with the inevitable result.
A subcategory within a particular genre: The academic mystery is a subgenre of the mystery novel. subcategory within a particular genre: The academic mystery is a subgenre of the mystery novel.
Subtyping, a form of polymorphism, is when calling code can be agnostic as to whether an object belongs to a parent class or one of its descendants. For example, a function might call make_full_name() on an object, which will work whether the object is of class Person or class Employee.