A markup language is a coding system, such as HTML and SGML, used to structure, index and link text files. A standard text coding system consists of a set of symbols inserted in a text document to control it's formatting and structure, the symbols are then processed which tells a screen or printer how the document should look.
Good summary - but it's not just about look. A markup language adds meaning to the content. Here is a snippet of XML which adds context to the word coco:
ReplyDeletecoco
I think you would agree that has nothing to do with look or style - but is markup none the less. To stretch yourself - investigate XML