Number sign

Number sign in Arial font

Number sign is one name for the symbol #, and is the preferred Unicode name for the codepoint represented by that glyph. The symbol is similar to the musical symbol sharp (♯). Several names for this symbol are used in the United States and Canada. In most other English-speaking countries, it is called a hash.

The sign's Unicode codepoint is U+0023 and its ASCII value is hexadecimal 23. On a UK keyboard, it has its own key just to the left of "Enter" and on a U.S. keyboard, it can be typed using Shift-3 (on a UK keyboard, this is the key combination for the pound sign).

In many parts of the world, including the United Kingdom, Canada, Australia, New Zealand, Russia and the rest of Europe the name, "number sign," is used for the sign "№". It is often written simply as No. or using a superscript N^o. To distinguish, the Unicode standard calls this sign the Numero sign (codepoint U+2116) to avoid confusion. Note that in these contexts, the # sign is not used to indicate a number or numerical value.

Naming convention within the USA

In the United States and Canada, the symbol was traditionally called the pound sign. This derives from a series of abbreviations for pound avoirdupois, which is a unit of mass (although pound is generally used as a unit of weight; for more information, see pound-force and pound (unit of mass)). At first "lb." was used; later, printers got a special font made up of an "lb" with a line through the ascenders so that the lowercase letter "l" would not be mistaken for the number "1". Unicode character U+2114 (℔) is called the "LB Bar Symbol," and it is a cursive development of this symbol. Finally came the reduction to two horizontal and two vertical strokes.

Its traditional commercial use in the U.S. was such that when it followed a number, it was to be read as "pounds", as in 5# of sugar, and when it preceded a number, it was to be read 'number', as in #2 pencil. Thus the same character in a printer's type case had two uses.

Other names in English

It has many other names (and uses) in English. (Those in bold are listed as alternative names in the Unicode documentation.)

• comment sign
  • from its use in many shell scripts and some programming languages like Perl to introduce comments
• crosshatch
  • resemblance
• fence, gate, grid, gridlet
  • resemblance
• hash / hash mark / hash sign
  • the most common name outside the U.S., including in the UK, Ireland, Australia, and New Zealand.
  • Used in Ireland, the UK, Australia, and New Zealand on touch-tone telephones – "Please press the hash key"
  • In the UK and Australia the symbol is often used as medical shorthand for 'fracture' [1][2]
  • Used among computer professionals. For example, in Unix scripting, it's used in combination with an exclamation mark to produce a "#!" or "hash-bang," used to tell the kernel which program to use to run the script.
• hex
  • from its use to denote hexadecimal values in some markup and programming languages
• mesh
  • introduced in the tonsil of the Intercal reference manual, and often reproduced in The Hacker's Dictionary
• octalthorpe / octothorp / octothorpe / octatherp
  • See wiktionary:Octothorpe for etymology. With some detail at www.octothorp.us.
  • See Doug Kerr's Octatherp article for detailed alternate etymology of octotherp.
  • See Encore magazine article "Pressing matters: touch-tone phones spark debates" for another attribution to Bell engineers, by 1968. Lauren Asplund, who provided the article, says that he and a colleague were the source of octothorp at AT&T engineering in New York in 1964.
  • The Merriam-Webster New Book of Word Histories, 1991, has a long article that's consistent with Doug Kerr's essay, in that it says octotherp was the original spelling, and that the word arose in the 1960s among telephone engineers.
  • The first appearance of octothorp in a U. S. patent is in a 1973 filing which also refers to the asterisk (*) as a sextile.[3]
  • http://www.worldwidewords.org/weirdwords/ww-oct1.htm tells of three possible etymologies, none likely, and says it wasn't in print until 1974, so the Merriam-Webster story that says it appeared in the 1960s may be more credible.
• pound
  • Used as the symbol for the pound (the unit of mass) in the U.S. (where lb. would be used in the UK and Canada; note that lb. or lbs. is common in the U.S. as well and is used by the general public more often than #). It is never called the pound sign in the UK, where that term always denotes the symbol for pounds sterling (£) rather than that for pounds weight (lb).
    • Keith Gordon Irwin in, The Romance of Writing, p. 125 says: "The Italian libbra (from the old Latin word libra, 'balance') represented a weight almost exactly equal to the avoirdupois pound of England. The Italian abbreviation of lb with a line drawn across the letters was used for both weights. The business clerks' hurried way of writing the abbreviation appears to have been responsible for the # sign used for pound."
  • Used in the U.S. and Canada on touch-tone telephones – "Please press the pound key"
• sharp
  • resemblance to the glyph used in music notation. Since most fonts don't contain the sharp sign most websites will doubtless continue to use the fallback hash mark. The music sharp sign, which should be used if available, is U+266F (♯).
  • so called in the name of the Microsoft-invented programming language, C#. However Microsoft says at Frequently Asked Questions About C#:
    It's not the "hash" (or pound) symbol as most people believe. It's actually supposed to be the musical sharp symbol. However, because the sharp symbol is not present on the standard keyboard, it's easier to type the hash ("#") symbol. The name of the language is, of course, pronounced "see sharp".
    According to the ECMA-334 C# Language Specification, section 6, Acronyms and abbreviations, the name of the language is written "C#" ("LATIN CAPITAL LETTER C (U+0043) followed by the NUMBER SIGN # (U+0023)") and pronounced "C Sharp".
  • In computing a shebang is the inexact contraction of sharp and bang the typical names of the # and ! signs used at the beginning of executable text files.
• space
  • used by editors to indicate where space should be inserted in a proof. This can mean (1) a line space (the space between two adjacent lines denoted by line # in the margin), (2) a hair space (the space between two letters in a word, denoted by hr #) (3) a word space, or letter space (the space between two words on a line, two letter spaces being ##). Em- and en-spaces (being the length of a letter m and n, respectively) are indicated by a square-shaped em- or en-quad character (  and  ̷, respectively).
• splat
  • colloquial term referring to the vague resemblance of a squashed insect
• square
  • occasionally used in the UK (e.g. sometimes in BT publications and automatic messages) - especially during the Prestel era, when the symbol was a page address delimiter
  • the International Telecommunications Union specification ITU-T E.161 3.2.2 states: "The # is to be known as a 'square' or the most commonly used equivalent term in other languages."
• widget

Other uses

In a URL the sign is used immediately after the URL of a webpage or other resource to introduce a "fragment identifier" — a name or id which defines a position within that resource or a section of the document. For example, in the URL http://en.wikipedia.org/wiki/Number_sign#Other_uses the portion after the # (Other_uses)is the fragment identifier (a link such as this will take you to a section in a web page, such as the 'In other languages' section of this article). A relative reference to the fragment from within the document itself can start with the number sign, and consist of just the fragment identifier: <a href="#top">TOC</a> refers to an anchor named "top" on the current web page. [4]

In the C programming language, the sign is used to introduce preprocessor directives.

In several assembly languages, the sign is used preceding an expression to denote an immediate value.

In writing press releases, the notation "###" indicates that there is no further copy to come.

In many countries, such as Norway, a "#" is used as a delimiter between different drugs on medical prescriptions. [5]

In other languages

• Arabic: "مربع", pronounced "morabaa" (square)
• Basque: Traol
• Bulgarian: диез, pronounced dies
• Catalan: Coixinet
• Chinese: "井號" (jǐng hào; literally: "well" sign) as it resembles the hanzi for water well, 井; jǐng
• Czech: mřížka (small grid or small bar); maltézský kříž (Maltese cross) used by Doc. Ing. Zdeněk Havlíček, CSc.
• Danish: firkant (tetragon, i.e. square), the official name used by telcos for touch-tone key, or havelåge (garden gate from the gate in a picket fence)
• Dutch: hekje (fence), spoorwegovergang (railroad crossing)
• Estonian: trellid (grate)
• Finnish: ruutu (square) or risuaita (brushwood fence)
• French: dièse (sharp sign) In Québec and Benelux it is called carré (square)
• German: Raute or Rautenzeichen (Rhombus, the official name used by telephone companies for the touch-tone key), Lattenzaun (picket fence), Doppelkreuz (double cross), Gatter (gate)
• Greek: δίεση (diesis)
• Hebrew: סוּלָמִית, pronounced sulamit (from sulam("ladder") + -it (diminutive))
• Hungarian: kettőskereszt (double cross)
• Italian: cancelletto (small gate)
• Japanese: "番号記号" (bangōkigō, "number sign"); "井桁" (igeta, literally the rim of a well, which is traditionally this shape) or "シャープ" (sharp in katakana)
• Latvian: restīte [IPA: restiːte] (little grid)
• Norwegian: firkant (tetragon, i.e. square) or (sometimes) skigard (A particular kind of fence with a visual resemblance)
• Persian: "چهارگوش" (Four-Corner) pronounced "Chaa'haa'r Goo'sh"
• Polish: kratka, krzyżyk (sharp sign), płotek, hash
• Portuguese: cardinal, used in mathematics notation to represent the cardinality of a set, sustenido ("sharp sign"), jogo-da-velha ("tic-tac-toe"). Also known as "cerquilha" in Brazil because it resembles a picket fence (cerca).
• Romanian: diez ("sharp sign")
• Russian: решётка (reshëtka), pronounced rye-SHOT-ka (grid)
• Serbian: taraba (fence)
• Slovak: mriežka ("small grid")
• Slovenian: lojtra (the official name used by telcos for the touch-tone key, a colloquial term for ladder)
• Spanish: numeral, cuadradillo, almohadilla ("cushion"), sostenido ("sharp sign"), michi, gato, tatetí (the last three meaning "tic-tac-toe")
• Swedish: stakettecken ("fence sign"), staket ("fence"), galler ("grid, grating") fyrkant ("square"), ruta ("square, box"), vedstapel ("stack of wood") or brädgård ("timberyard")
• Swiss German: Gartehag (fence)
• Thai: เครื่องหมายสี่เหลี่ยม (square sign, only used in telephone service)
• Turkish: Sayı işareti

See also

• Numero sign

References (as numbered above)

1. Weird Words
   • Entry for this symbol: http://www.quinion.com/words/weirdwords/ww-oct1.htm – valid as of May 22, 2003
2. World Heritage Dictionary
   • Entry for this symbol: http://www.bartleby.com/61/88/O0028850.html – valid as of May 22, 2003