Number sign

The symbol # is called the number sign, hash, octothorp and sometimes the pound sign (not to be confused with the currency symbol of the same name). Historically, it has had use for several purposes such as showing an ordinal number and the pound as a unit of mass.

Since 2007, the symbol became famous after it was used in hashtags across social media.

Names

Number sign

This is the name chosen by the Unicode Consortium, which is most common in Canada and the United States.

Pound sign

In Canada and the United States, the # key on a phone is called the pound sign, pound key, or simply pound. This name is rarely used elsewhere because it can refer to the currency symbol £.

Hash

In the United Kingdom and Australia, it is often called a hash because it resembles cross-hatching.

The term appeared in South African writings from the 1960s.

Use

Computing

  • In Unicode and ASCII, the number sign has the codepoint U+0023 # NUMBER SIGN and entity code # in HTML5.
  • It is also used for numbered lists in HTML.

References

  1. ↑ Houston, Keith (2013). Shady characters: the secret life of punctuation, symbols, & other typographical marks (1st ed.). New York ; London: W.W. Norton & Company. ISBN 978-0-393-06442-1.
  2. ↑ Barber, Katherine, ed. (2004). Canadian Oxford dictionary. Oxford reference online premium (2nd ed.). Oxford: Oxford Univ. Press. ISBN 978-0-19-541816-3.
  3. ↑ Safire, William (1991-03-24). "On Language; Hit the Pound Sign". The New York Times. ISSN 0362-4331. Retrieved 2026-10-15.
  4. ↑ Dowling, Tim (2010-12-08). "How the # became the sign of our times". The Guardian. ISSN 0261-3077. Retrieved 2026-10-15.
  5. ↑ Proofed (2020-02-06). "Writing Tips: How to Use the Hash Sign (#) | Proofed's Writing Tips". Proofed. Retrieved 2026-10-15.
  6. ↑ "hash, n.1 : Oxford English Dictionary". www.oed.com. Retrieved 2026-10-15.
  7. ↑ "HASH MARK Definition & Meaning | Dictionary.com". www.dictionary.com. Retrieved 2026-10-15.
  8. ↑ Research Review. Navorsingsoorsig vols. 18–21, pp. 117, 259 (1968)
  9. https://web.archive.org/web/20180403112505/https://en.oxforddictionaries.com/definition/number_sign
  10. Piercy, Joseph (2013-10-25). Symbols: A Universal Language. Michael O'Mara Books. ISBN 978-1-78243-073-5.