Editing Number sign (section)

{{Short description|Typographic symbol (#)}}
{{distinguish|text=the [[Numero sign]] (№), or [[Sharp (music)]] (♯)}}
{{Infobox symbol
  |mark = <nowiki>#</nowiki>
  |unicode = {{unichar|0023|html=}}
  |different from = {{unichar|266F|nlink=}}<br />{{unichar|2317|nlink=}}<br />{{unichar|22D5|nlink=}}<br />{{unichar|4E95|nlink=}}
  |see also = {{unichar|00A3|nlink=}}<br />{{unichar|2116|nlink=}}
}}

The symbol {{char|'''#'''}} is known <!-- This is a list exclusively of names that appear in established dictionaries and encyclopedias. Please do not add nicknames, memes, or other variations that do not have such support. -->as the '''number sign''',<ref name="oedNumberSign">{{cite web|url=https://en.oxforddictionaries.com/definition/number_sign|archive-url=https://web.archive.org/web/20180403112505/https://en.oxforddictionaries.com/definition/number_sign|url-status=dead|archive-date=April 3, 2018|title=number sign|website=Oxford English Dictionary}}</ref> '''hash''',<ref name="oedHash">{{cite web|url=https://en.oxforddictionaries.com/definition/hash|archive-url=https://web.archive.org/web/20171231152808/https://en.oxforddictionaries.com/definition/hash|url-status=dead|archive-date=December 31, 2017|title=hash|website=Oxford English Dictionary}}</ref> or '''pound sign'''<ref>{{cite web|url=https://en.oxforddictionaries.com/definition/pound_sign|archive-url=https://web.archive.org/web/20180403051651/https://en.oxforddictionaries.com/definition/pound_sign|url-status=dead|archive-date=April 3, 2018|title=pound sign|website=Oxford English Dictionary|access-date=5 May 2016}}</ref> (only "hash" is used outside North America). The symbol has historically been used for a wide range of purposes including the designation of an ordinal number and as a [[Typographic ligature|ligatured]] abbreviation for [[Pound (mass)|pounds avoirdupois]] – having been derived from the now-rare {{char|℔}}.<ref name="Houston">{{cite book |last1=Houston|first1=Keith |title=Shady Characters: The Secret Life of Punctuation, Symbols, and Other Typographical Marks |publisher=W. W. Norton & Company |year=2013 |isbn=978-0-393-06442-1 |chapter-url=https://books.google.com/books?id=3fbWAAAAQBAJ&pg=PA41 |pages=41–57 |chapter=The Octothorpe }}</ref>

Since 2007, widespread usage of the symbol to introduce [[metadata tag]]s on [[social media]] platforms has led to such tags being known as "[[hashtag]]s",<ref>{{cite book|last=Piercy |first=Joseph |title=Symbols: A Universal Language|chapter-url=https://books.google.com/books?id=XRbdAgAAQBAJ&pg=PT84 |chapter=Part III: Symbnols of value, ownership and exchange |access-date=4 October 2014 |date=25 October 2013 |publisher=Michael OMara|isbn=978-1-78243-073-5 |pages=84–85}}</ref> and from that, the symbol itself is sometimes called a '''hashtag'''.<ref name=hashtag>{{cite web |url=https://www.britannica.com/dictionary/eb/qa/why-is-the-symbol-called-the-hashtag-in-twitter |title=Why is the symbol # called the hashtag in Twitter? |website=The Britannica Dictionary |access-date=2022-09-23 |archive-date=2022-09-23 |archive-url=https://web.archive.org/web/20220923225746/https://www.britannica.com/dictionary/eb/qa/why-is-the-symbol-called-the-hashtag-in-twitter |url-status=live }}</ref>

The symbol is distinguished from similar symbols by its combination of level horizontal strokes and right-tilting vertical strokes.