A markup language is a computer language used to clarify a document’s content. It was designed to process, define, and present computer text in a form that humans can read. It specifies the code used to format text, including the style and layout the programmer wants the document to appear in. It uses tags to define these elements.

You can think of using markup language as a teacher grading students’ exams. The teacher “marks” mistakes, so students know why they were given a particular score.

Other interesting terms…

Read More about a “Markup Language”

What is a Markup Language

What Are the Most Popular Markup Languages Used Today?

We compiled a list of some of the most commonly used markup languages below.


HyperText Markup Language (HTML) is perhaps the most widely used markup language today. It is mainly used to develop the web pages we see on the World Wide Web. Essentially, every web page can be written using a version of HTML. That makes the code critical in ensuring that the text and images on a website follow proper formatting. Without it, browsers would have no clue how the content should be displayed.

HTML is also responsible for giving web pages their basic structure. It is often used with Cascading Style Sheets (CSS) to improve page appearance.


eXtensible Markup Language (XML) is highly similar to HTML. It allows browsers to display and interpret information correctly. But as its name implies, XML is extensible. It permits a tag to define itself based on a given description of the content rather than just display it.


Bulletin Board Code (BBC or BBCode) is commonly used to format posts in message boards. The tags are usually placed in-between square brackets ([ ]) before they undergo parsing or breaking down sentences into parts to describe their roles on the message board system. The code is then translated to a markup language that most web browsers can interpret, usually in HTML. Some message boards prefer using BBC since it allows markups to be done without triggering security alerts when forum users use HTML code in their posts.


Standard Generalized Markup Language (SGML) is an International Organization for Standardization (ISO) standard that provides a general structure for all markup languages. It outlines the rules used to validate and parse markups. Note, though, that not all markup languages, such as HTML5, adhere to the SGML standard.

Markup Language versus Programming Language: What’s the Difference?

Markup languages are sometimes confused with programming languages, but they are entirely different. A markup language refers to a series of tags mixed with plain text. If deleted, plain text could be interpreted in a wholly different manner, such as a bulleted or numbered list. Markup languages tell browsers what rules to follow, so the text remains human-readable.

In contrast, programming languages provide a set of commands for writing programs or applications that any computer can understand.

To illustrate, HTML lets you read this entry because it was coded with a markup language on our website. Even if you remove the CSS or JavaScript (JS) codes, humans can still read most of the content but may not see embedded videos. For all of the web page’s functionality to work, such as the search box, our developer needs to use a programming language, such as Perl, PHP, or JS, on it.

Knowing the answer to “What is a markup language?” hopefully helped you understand what it takes to put websites together.

Key Takeaways

  • Markup languages are computer languages used to clarify the content of a document by using tags to define its elements, such as headings, paragraphs, and images.
  • The most popular markup languages include HTML, XML, BBC, and SGML.
  • Markup languages differ from programming languages. Markup languages are used to format text, while programming languages are for creating programs and applications.
  • HTML is one of the most commonly used markup languages today. It is used to create web pages.
  • XML is similar to HTML but is extensible, meaning new tags can be created with it. XML is used to store and exchange data in various formats.
  • BBC is a markup language commonly used to format posts in message boards.
  • SGML is a standard that provides a general structure for all markup languages.