Markdown is described as 'Text-to-HTML conversion tool for web writers. Markdown allows you to write using an easy-to-read, easy-to-write plain text format, then convert it to structurally valid XHTML (or HTML)' and is a very popular Markup Language in the development category. There are more than 10 alternatives to Markdown for a variety of platforms, including Mac, Windows, Linux, Self-Hosted and BSD apps. The best Markdown alternative is Quarkdown, which is both free and Open Source. Other great apps like Markdown are LaTeX, HTML, CommonMark and R Markdown.
meml its a simple version of html, with more efficient and modern syntax.