A programming language is a type of written language that tells computers what to do. Examples are: Python, Ruby, Java, JavaScript, C, C++, and C#. HTML is a markup language, in a technical sense not a programming language, since a program can't be made with it, while it still does tell the computer, i.e. web browser, what information to display. Neither is CSS, these languages are used to make web pages, they can be used to make static web pages, while often one or more programming languages are used additionally to make a dynamic web page. Neither are notebook environments programming languages (while often used by programmers), such one of the more popular ones, Jupyter, that is made for many programming languages, such as Julia, Python, and R (most often users choose to use only one programming language with it, one of those three officially supported and the project named after, or some other language). Programming languages are used to write all computer programs and computer software. A programming language is like a set of instructions that the computer follows to do something.