In the Unified Modeling Language

Unified Modeling Language

Unified Modeling Language is a standardized general-purpose modeling language in the field of object-oriented software engineering. The standard is managed, and was created, by the Object Management Group...

 1.x, powertype is a keyword

Keyword (computer programming)

In computer programming, a keyword is a word or identifier that has a particular meaning to the programming language. The meaning of keywords — and, indeed, the meaning of the notion of keyword — differs widely from language to language....

 for a specific UML stereotype, and applies to a class

Class (computer science)

In object-oriented programming, a class is a construct that is used as a blueprint to create instances of itself – referred to as class instances, class objects, instance objects or simply objects. A class defines constituent members which enable these class instances to have state and behavior...

 or dependency

Dependency (UML)

A dependency in the Unified Modeling Language exists between two defined elements if a change to the definition of one may result in a change to the other...

. Powertype shows a classifier

Classifier (UML)

A classifier is a category of Unified Modeling Language elements that have some common features, such as attributes or methods.A classifier is an abstract metaclass classification concept that serves as a mechanism to show interfaces, classes, datatypes and components.A classifier describes a set...

 whose instances (object

Object (computer science)

In computer science, an object is any entity that can be manipulated by the commands of a programming language, such as a value, variable, function, or data structure...

s) are children of the given parent

Parent

A parent is a caretaker of the offspring in their own species. In humans, a parent is of a child . Children can have one or more parents, but they must have two biological parents. Biological parents consist of the male who sired the child and the female who gave birth to the child...

.

In UML 2.x, a powertype is a metaclass

Metaclass

In object-oriented programming, a metaclass is a class whose instances are classes. Just as an ordinary class defines the behavior of certain objects, a metaclass defines the behavior of certain classes and their instances. Not all object-oriented programming languages support metaclasses...

whose instances are subclasses of a given class. The stereotype has been removed and the powertype is now indicated by typing the generalization set.