Tk
Tk is a library which generalizes graphical user interface operations to allow an application which uses the library to have a functional GUI in any of a variety of environments.
Tk is most commonly combined with TCL, but may be used with programs written in many other programming languages.
Library
This is an example of a library. You may see a list of other libraries used on Rosetta Code at Category:Solutions by Library.
This is an example of a library. You may see a list of other libraries used on Rosetta Code at Category:Solutions by Library.