What are Markup Languages?

Formal (computer) languages that allow to use in addition to the normal text in natural languages ​​also syntactically distinguishable constructs specifying the structure of the text, the meaning of parts, etc., and also allows the text to store its metadata (information about the origin, content, authorship, dating, rights used ...).

Known markup languages ​​( markup languages ​​) are languages ​​for web ( HTML, XML, ...), but also others such as typesetting formats of the           TeX system, text (documentation/help) ​​formatting tools for the UNIX-like systems           nroff, troff. Languages for page description for printing and presentation, namely PostScript or PDF have similar characteristics (text + markup or commands).