Editing Markup language (section)

{{Short description|Modern system for annotating a document}}
[[File:RecipeML egg nog.svg|thumb|Example of [[RecipeML]], a simple markup language based on XML for creating recipes. The markup can be converted programmatically for display into, for example, [[HTML]], [[Portable Document Format|PDF]] or [[Rich Text Format]].|alt=A screenshot of an XML file.]]
A '''markup''' '''language''' is a [[Encoding|text-encoding system]] which specifies the structure and formatting of a document and potentially the relationships among its parts.<ref>{{Cite news |title=markup language {{!}} Definition, Examples, & Facts |language=en |work=Encyclopedia Britannica |url=https://www.britannica.com/technology/markup-language |access-date=2022-08-17 |archive-date=2020-10-26 |archive-url=https://web.archive.org/web/20201026080719/https://www.britannica.com/technology/markup-language |url-status=live }}</ref> Markup can control the display of a document or enrich its content to facilitate automated processing.

A markup language is a set of rules governing what markup information may be included in a document and how it is combined with the content of the document in a way to facilitate use by humans and computer programs. The idea and [[terminology]] evolved from the "marking up" of paper [[manuscript]]s (e.g., with revision instructions by editors), traditionally written with a red pen or [[blue pencil (editing)|blue pencil]] on authors' manuscripts.<ref>{{cite book|author1-last=Siechert
|author1-first=Carl |author2-last=Bott |author2-first=Ed|title=Microsoft Office Inside Out: 2013 Edition |url=https://books.google.com/books?id=TbhCAwAAQBAJ|year=2013 |publisher=Pearson Education |isbn=978-0735669062 |page=305 |quote=Some reviewers prefer going old school by using a red pen on printed output}}</ref>

Older markup languages, which typically focus on typography and presentation, include [[Troff]], [[TeX]], and [[LaTeX]].
[[Scribe (markup language)|Scribe]] and most modern markup languages, such as [[Extensible Markup Language|XML]], identify document components (for example headings, paragraphs, and tables), with the expectation that technology, such as [[Style sheet (web development)|stylesheets]], will be used to apply formatting or other processing.{{Citation needed|date=February 2024}}

Some markup languages, such as the widely used [[HTML]], have pre-defined [[presentation semantics]], meaning that their specifications prescribe some aspects of how to present the [[structured data]] on particular media. HTML, like [[DocBook]], [[Open eBook]], [[JATS]], and many others, is based on the markup metalanguages [[Standard Generalized Markup Language|SGML]] and [[XML]]. That is, SGML and XML allow designers to specify particular [[XML schema|schema]]s, which determine which elements, attributes, and other features are permitted, and where.<ref>{{cite web |author=<!-- not stated --> |date=<!-- not stated --> |url=https://sgmljs.net/docs/markdown-typography-examples.html# |website=smljs.net |title=SGML Markdown Typography Documentation |access-date=2025-01-02}}</ref>

A key characteristic of most markup languages is that they allow intermingling markup with document content such as text and pictures. For example, if a few words in a [[Sentence (linguistics)|sentence]] need to be emphasized, or identified as a proper name, defined term, or another special item, the markup may be inserted between the characters of the sentence.