Interpunct

An interpunct ( · )—also called an interpoint—is a small dot used for interword separation in ancient Latin script.

The dot is vertically centered, e.g. "DONA·EIS·REQVIEM", and is therefore also called a middle dot or centered dot (Commonwealth: centred dot). In addition to the round dot form, inscriptions sometimes use a small equilateral triangle for the interpunct, pointing either up or down. Such triangles can be found on inscriptions on buildings in the twentieth century. Ancient Greek, by contrast, had not developed interpuncts; all the letters ran together. The use of spaces for word separation did not appear until much later, some time between 600 and 800 AD.

The middle dot or dot operator (often visually identical to the interpunct), is the primary multiplication sign (instead of the × used in English-speaking countries): “a multiplied by b” is written either explicitly as a·b or implicitly as ab, depending on context.

On a Mac OS X system, this symbol can be typed by "option-shift-9," and on X by "AltGr-.". In Unicode, the interpunct is code point U+00B7, or 0183 in decimal. The HTML entity for an interpunct is · or · (introduced in HTML 3.2). See also "Similar symbols", below.

In written language

English

In British typography, an interpunct · is sometimes called a space dot. Dictionaries often use the interpunct to indicate syllabification.

In some word processors, interpuncts are used to denote either hard space or space characters. In others, it is used to indicate a space when put in paragraph format to show indentations and spaces.

It is also used as a decimal point, e.g. 7·85, although this usage has declined in recent decades.

Shavian

In the Shavian alphabet of English, the middle dot is used before a word to denote it as a proper noun.

Catalan

In Catalan, the [punt volat] Error: {{Lang}}: text has italic markup (help) (literally, "flown dot") is used between two ls (thus: l·l) in cases where each belongs to a separate syllable (e.g. [col·lecció] Error: {{Lang}}: text has italic markup (help), 'collection'). This is to distinguish the true "double-l" pronunciation from that of the letter-combination ll (without a dot) which in Catalan stands for palatal lateral [ʎ] (lloc "place", castellà "Castilian", castell "castle").

The combination of two ls and a raised dot is a typical feature of Catalan texts.

In orthographic descriptions, l·l is called [ela geminada] Error: {{Lang}}: text has italic markup (help) ("geminate l") and ll [doble ela] Error: {{Lang}}: text has italic markup (help). Although considered as a spelling mistake, a period or a hyphen is frequently used when a middle dot is unavailable: [col.lecció] Error: {{Lang}}: text has italic markup (help) or [col-lecció] Error: {{Lang}}: text has italic markup (help). Unicode has unique code points for the letters Ŀ (U+013F) and ŀ (U+0140), but they are compatibility characters and are not frequently used nor recommended. The preferred Unicode representation is l· (U+006C + U+00B7). The use of • bullet (U+2022, •) is strongly discouraged on aesthetic grounds.

In Medieval Catalan the symbol '·' was sometimes used to note certain elisions, much like the modern apostrophe. (See Occitan below.)

Since there are no separate keyboard layouts for languages (only for countries), punt volat can be typed using Shift-3 in the Spanish (Spain) layout.

Chinese

The Chinese language sometimes uses the interpunct (called the partition sign) to separate the given name and the family name of non-Chinese, or unsinicized or desinicized minority ethnic groups in China, for example, 威廉·莎士比亚 (Weilian·Shashibiya) is the transliteration of "William Shakespeare", and the partition sign is inserted in between the characters signifying the sound of "William" and those for "Shakespeare". The Chinese partition sign is also used to separate book title and chapter title when they are mentioned consecutively (with book title first, then chapter).

In Chinese, the middle dot is also fullwidth in printed matter, but the regular middle dot (·) is used in computer input, which is then rendered as fullwidth in Chinese-language fonts. Note that while some fonts may render the Japanese katakana middle dot as a square under great magnification, this is not a defining property of the middle dot that is used in China or Japan.

Swedish sinologist Bernhard Karlgren used a middle dot to represent the glottal stop in his reconstruction of medieval Chinese.

See also proper name mark.

Taiwanese Minnan

In Pe̍h-ōe-jī for Taiwanese Hokkien, middle dot is often used as a workaround for dot above right diacritic because most early encoding systems did not support this diacritic. This is now encoded as U+0358 COMBINING DOT ABOVE RIGHT (see o͘). Unicode did not support this diacritic until June 2004. Newer fonts often support it natively; however, the practice of using middle dot still exists. Historically, it was derived in the late 19th century from an older barred-o with curly tail as an adaptation to the typewriter.

Franco-Provençal

In Franco-Provençal (or Arpitan), the interpunct is used in order to distinguish the following graphemes:

• ch·, pronounced [ʃ], versus ch, pronounced [ts]
• j·, pronounced [ʒ], versus j, pronounced [dz]
• g· before e, i, pronounced [ʒ], versus g before e, i, pronounced [dz]

Georgian language

The Georgian language uses · (middot) as a comma.

Greek

The Greek ánō stigmē (άνω στιγμή, lit. "upper dot") is a punctuation mark equivalent to the semicolon and is sometimes written as a middle dot. Although Unicode provides a unique code point for it (U+0387), U+00B7 is preferred.

Japanese

Main article: Japanese punctuation

Interpuncts are often used to separate transcribed foreign words written in Katakana. For example, "Can't Buy Me Love" becomes 「キャント・バイ・ミー・ラヴ」 (Kyanto·bai·mī·ravu). A middle dot is also sometimes used to separate lists in Japanese instead of the Japanese comma ("、" known as tōten). Grammar lessons in Japanese sometimes also use a similar symbol to separate a verb suffix from its root.

However, the Japanese writing system usually does not use space or punctuations to separate words; instead, the mixture of katakana, kanji, and hiragana gives some indication of word boundary.

In Japanese typography, the "katakana middle dot" (as the Unicode consortium calls it) has a fixed width that is the same as most kana characters, known as fullwidth.

Korean

Interpuncts are used in written Korean to denote a list of two or more words, more or less in the same way a slash (/) is used to juxtapose words in many other languages. The use of interpuncts has declined in years of digital typography and especially in place of slashes, but in the strictest sense, a slash cannot replace a middle dot in Korean typography.

Latin

The dot called interpunct was used regularly in early Latin to separate words, but has long been replaced by space.

Occitan

In Occitan, especially in the Gascon dialect, the interpunct (punt interior, literally, "inner dot", or ponch naut for "high/upper point") is used to distinguish the following graphemes:

• s·h, pronounced [s.h], versus sh, pronounced [ʃ], for example, in des·har 'to undo' vs. deishar 'to leave'
• n·h, pronounced [n.h], versus nh, pronounced [ɲ], for example in in·hèrn 'hell' vs. vinha 'vineyard'

Although it is considered to be a spelling error, a period is frequently used when a middle dot is unavailable: des.har, in.hèrn, which is the case for French keyboard layout.

In Medieval Occitan, the symbol · was sometimes used to denote certain elisions, much like the modern apostrophe, the only difference being that the word that gets to be elided is always placed after the interpunct, the word before ending either in a vowel sound or the letter n:

• que·l (que lo, that the) versus qu'el (that he)
• From Bertran de Born's Ab joi mou lo vers e·l comens (translated by James H. Donalson):

Bela Domna·l vostre cors gens E·lh vostre bel olh m'an conquis, E·l doutz esgartz e lo clars vis, E·l vostre bels essenhamens, Que, can be m'en pren esmansa, De beutat no·us trob egansa: La genser etz c'om posc'e·l mon chauzir, O no·i vei clar dels olhs ab que·us remir.

Domna·l [ˈdonnal] = Domna, lo ("Lady, the": singular definite article) E·lh [eʎ] = E li ("And the": plural definite article) E·l [el] = E lo ("And the") E·l = E lo ("And the") No·us [nows] = Non vos ("(do) not... you": direct object pronoun) E·l = En lo ("in the") No·i [noj] = Non i ("(do) not... there") Que·us [kews] = Que vos ("that (I)... you")

O pretty lady, all your grace and eyes of beauty conquered me, sweet glance and brightness of your face and all your nature has to tell so if I make an appraisal I find no one like in beauty: most pleasing to be found in all the world or else the eyes I see you with have dimmed.

Old Irish

In many linguistic works discussing Old Irish (but not in actual Old Irish manuscripts), the interpunct is used to separate a pretonic preverbal element from the stressed syllable of the verb, e.g. [do·beir] Error: {{Lang}}: text has italic markup (help) "says". It is also used in citing the verb forms used after such preverbal elements, e.g. [·beir] Error: {{Lang}}: text has italic markup (help) "carries", to distinguish them from forms used without preverbs, e.g. [beirid] Error: {{Lang}}: text has italic markup (help) "carries". In other works, the hyphen ([do-beir, -beir] Error: {{Lang}}: text has italic markup (help)) or colon ([do:beir, :beir] Error: {{Lang}}: text has italic markup (help)) may be used for this purpose.

Runes

Runic texts use either a interpunct-like or a colon-like punctuation mark to separate words. There are two Unicode characters dedicated for this: U+16EB and U+16EC.

In mathematics and science

In British publications up to the mid-1970s, especially scientific and mathematical texts, the decimal point was commonly typeset as a middle dot. When the British currency was decimalised in 1971, the official advice issued was to write decimal amounts with a raised point (thus: £21·48) and to use a decimal point "on the line" only when typesetting constraints made it unavoidable. The widespread introduction of electronic typewriters and calculators soon afterwards was probably a major factor contributing to the decline of the raised decimal point, although it can still sometimes be encountered in academic circles (e.g., Cambridge University 2006) and its use is still enforced by some UK-based academic journals such as The Lancet.

In SI units the middle dot or a NBSP is used as a multiply. Only a comma , or period . may be used as a decimal marker.

In mathematics, a small middle dot can be used to represent the product; for example, x ∙ y for the product of x and y. When dealing with scalars, it is interchangeable with the multiplication sign: x ⋅ y means the same thing as x × y, but × is easily confused with the letter x. However, when dealing with vectors, the dot product is distinct from the cross product. This usage has its own designated code point in Unicode, U+2219 (∙), called the "bullet operator". It is also sometimes used to denote the “AND” relationship in formal logic, due to the relationship between these two operations. In situations where the interpunct is used as a decimal point (as noted above, by many mathematics teachers in some countries), then the multiplication sign used is usually a period, not an interpunct.

In computing, the middle dot is usually used to indicate white space in various software applications such as word processing, graphic design, web layout, desktop publishing, or software development programs. It allows the user to see where white space is located in the document, and what sizes of white space are used, since normally white space is invisible so tabs, spaces, non-breaking spaces, and such are indistinguishable from one another.

In chemistry, the middle dot is used to separate the parts of formulas of addition compounds, mixture salts or solvates (mostly hydrates), such as of copper(II) sulfate pentahydrate, CuSO₄ · 5H₂O.

Similar symbols

Symbol	Character Entity	Numeric Entity	Unicode Code Point	Notes
·	·	·	U+00B7	interpunct, middle dot
·		·	U+0387	Greek ánō stigmē
᛫		᛫	U+16eb	Runic punctuation
⋅	⋅	⋅	U+22C5	dot operator (mathematics)
∙		∙	U+2219	bullet operator (mathematics)
•	•	•	U+2022	bullet, often used to mark list items
‧		‧	U+2027	hyphenation point (dictionaries)
・		・	U+30FB	fullwidth katakana middle dot
･		･	U+FF65	halfwidth katakana middle dot
ּ		ּ	U+05BC	Hebrew point dagesh or mapiq

Characters in the Symbol column above may not render correctly in all browsers.

For most North American Microsoft operating systems using OEM Code page 437, the Alt code is 250.

See also

• Punctuation