What is Markup Language ?

Question

other than HTML .. which language is a Markup language as well ?

Answer 1

@Lily Chong wrote: "i understand that you can define your own tag in XML . can you do so in XHTML ?"

No, you can't...
XML is used to define XHTML, as it is used to define other markups languages as SVG... but you don't have access to definitions of these languages syntax, as contraly when you use XML to define your own data structure ( language -- and so creating xhatever tag you want, as you will be in charge to provide paser to use these data ).

Anyway, XHtml is deprecated: it was a branch of Html development for redefine Html with XML instead of SGML ( Standardized Generic Markup Language -- on which is based too XML ), abandonned with becoming of Html5... as it's based on XML, it's more strict than Html ( wich is permissive: invalid codes are displaying as well possible ), and was less or more equivalent to Html 4.01, the previous version of the actual: there's definitively no reason at all to continue to use it :P

Answer 2

A markup language is the one that uses tags.
Example HTML XML etc

Answer 3

i understand that you can define your own tag in XML . can you do so in XHTML ?