XHTML
XHTML is the acronym for Extensible HyperText Markup Language.

Extensible HyperText Markup Language
A part of the family of XML markup languages and mirrors or extends versions of the widely used Hypertext Markup Language (HTML), the language in which web pages are formulated. XHTML was developed by the World Wide Web Consortium (W3C) to help web developers create pages that can be displayed consistently across different types of browsers and devices. It combines the flexibility of HTML with the stricter syntax of XML, ensuring more rigorous coding standards for web development.