A markup language is a system for annotating a document in a way that is distinguishable from the actual body of text itself. The concept originates from the marking up of paper manuscripts by editors with a different coloured pen. In computing, the red pen instructions have been replaced with tags that describe something about the text in the enclosed tags, depending on the language these tags can describe things such as: positioning on a page, formatting (such as colour or font) or just define what the enclosed text means.