Markup Concept

Markup, based on a markup language, is a modern system for annotating a text in a way that is syntactically distinguishable from the original source text. The idea and terminology evolved from the "marking up" of manuscripts, i.e. the revision instructions by editors, traditionally written with a blue pencil on authors' manuscripts. Markup is typically omitted from the version of the text which is displayed for end-user consumption. Some markup languages, like HTML, have presentation semantics, meaning their specification prescribes how the structured data is to be presented, but other markup languages, like XML, have no predefined semantics.