Thecomma (,) is apunctuation mark that appears in several variants in different languages. Sometypefaces render it as a small line, slightly curved or straight, but inclined from the vertical; others give it the appearance of a miniature filled-in figure9 placed on thebaseline. In many typefaces it is the same shape as anapostrophe or single closingquotation mark’.
The comma is used in many contexts andlanguages, mainly to separate parts of asentence such asclauses, and items in lists mainly when there are three or more items listed. The wordcomma comes from theGreekκόμμα (kómma), which originally meant a cut-off piece, specifically ingrammar, a shortclause.[1][2]
The development ofpunctuation is much more recent than the alphabet.
In the 3rd century BC,Aristophanes of Byzantium invented a system of singledots (théseis) at varying levels, which separated verses and indicated the amount of breath needed to complete each fragment of the text whenreading aloud.[4] The different lengths were signified by a dot at the bottom, middle, or top of the line. For a short passage, akomma in the form of a dot⟨·⟩ was placed mid-level. This is the origin of the concept of a comma, although the name came to be used for the mark itself instead of the clause it separated.
The mark used today is descended from a/, a diagonalslash known asvirgula suspensiva, used from the 13th to 17th centuries to represent a pause. The modern comma was first used byAldus Manutius.[5][6]
In general, the comma shows that the words immediately before the comma are less closely or exclusively linkedgrammatically to those immediately after the comma than they might be otherwise. The comma performs a number of functions inEnglish writing. It is used in generally similar ways in other languages, particularly European ones, although the rules on comma usage – and their rigidity – vary from language to language.
Commas are placed between items in lists, as inThey own a cat, a dog, two rabbits, and seven mice.
Whether the final conjunction, most frequentlyand, should be preceded by a comma, called theserial comma, is one of the most disputed linguistic or stylistic questions in English:
They served apples, peaches, and bananas. (serial comma used)
They served apples, peaches and bananas. (serial comma omitted)
The serial comma is also known as the Oxford comma, Harvard comma, or series comma. Although less common in British English, its usage occurs within both American and British English. It is called the Oxford comma because of its long history of use by Oxford University Press.[8]
According toNew Hart's Rules, "house style will dictate" whether to use the serial comma. "The general rule is that one style or the other should be used consistently." No association with region or dialect is suggested, other than that its use has been strongly advocated by Oxford University Press.[9] Its use is preferred byFowler'sModern English Usage. It is recommended by the United StatesGovernment Printing Office,Harvard University Press, and the classicElements of Style ofStrunk and White.
Use of a comma may prevent ambiguity:
The sentenceI spoke to the boys, Sam and Tom could mean eitherI spoke to the boys and Sam and Tom (I spoke to more than three people) orI spoke to the boys, who are Sam and Tom (I spoke to two people);
I spoke to the boys, Sam, and Tom – must bethe boys and Sam and Tom (I spoke to more than three people).
The serial comma does not eliminate all confusion. Consider the following sentence:
I thank my mother, Anne Smith, and Thomas. This could mean eithermy mother and Anne Smith and Thomas (three people) ormy mother, who is Anne Smith; and Thomas (two people). This sentence might be recast as "my mother (Anne Smith) and Thomas" for clarity.
I thank my mother, Anne Smith and Thomas. Because the comma after "mother" is conventionally used to prepare the reader for anappositive phrase – that is, a renaming of or further information about a noun – this construction formally suggests that my mother's name is "Anne Smith and Thomas". Because that is implausible, it is relatively clear that the construction refers to two separate people. Compare "I thank my friend, Smith and Wesson", in which the ambiguity is obvious to those who recogniseSmith and Wesson as a business name.
As arule of thumb,The Guardian Style Guide[10] suggests that straightforward lists (he ate ham, eggs and chips) do not need a comma before the final "and", but sometimes it can help the reader (he ate cereal, kippers, bacon, eggs, toast and marmalade, and tea).The Chicago Manual of Style and other academic writing guides require the serial comma: all lists must have a comma before the "and" prefacing the last item in a series (seeDifferences between American and British usage below).
If the individual items of a list are long, complex, affixed with description, or themselves contain commas,semicolons may be preferred as separators, and the list may be introduced with acolon.
Innews headlines, a comma might replace the word "and", even if there are only two items, in order to save space, as in this headline from Reuters:[11]
Trump, Macron engage in a little handshake diplomacy.
Commas are often used to separateclauses. In English, a comma is often used to separate adependent clause from theindependent clause if the dependent clause comes first:After I fed the cat, I brushed my clothes. (Compare this withI brushed my clothes after I fed the cat.) Arelative clause takes commas if it is non-restrictive, as inI cut down all the trees, which were over six feet tall. (Without the comma, this would mean that only the trees more than six feet tall were cut down.) Some style guides prescribe that twoindependent clauses joined by a coordinatingconjunction (for,and,nor,but,or,yet,so) must be separated by a comma placed before the conjunction.[12][13] In the following sentences, where the second clause is independent (because it can stand alone as a sentence), the comma is considered by those guides to be necessary:
Mary walked to the party, but she was unable to walk home.
Designer clothes are silly, and I can't afford them anyway.
Don't push that button, or twelve tons of high explosives will go off right under our feet!
In the following sentences, where the second half of the sentence is a dependent clause (because it does not contain an explicitsubject), those guides prescribe that the comma be omitted:
Mary walked to the party but was unable to walk home.
I think designer clothes are silly and can't afford them anyway.
However, such guides permit the comma to be omitted if the second independent clause is very short, typically when the second independent clause is animperative,[12][13] as in:
Sit down and shut up.
The above guidance is not universally accepted or applied. Longcoordinate clauses, particularly when separated by "but", are often separated by commas:[14]
She had very little to live on, but would never have dreamed of taking what was not hers.
In some languages, such asGerman andPolish, stricter rules apply on comma use between clauses, with dependent clauses always being set off with commas, and commas being generally proscribed before certain coordinating conjunctions.
The joining of two independent sentences with a comma and no conjunction (as in"It is nearly half past five, we cannot reach town before dark.") is known as acomma splice and is sometimes considered an error in English;[15] in most cases a semicolon should be used instead. A comma splice should not be confused, though, with the literary device calledasyndeton, in which coordinating conjunctions are purposely omitted for a specific stylistic effect.
A much debated comma is the one in theSecond Amendment to the United States Constitution, which says"A well regulated Militia being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed." but ratified by several states as"A well regulated Militia being necessary to the security of a free State, the right of the people to keep and bear Arms shall not be infringed." which has caused much debate on its interpretation.
Commas are always used to set off certainadverbs at the beginning of a sentence, includinghowever,in fact,therefore,nevertheless,moreover,furthermore, andstill.
Therefore, a comma would be appropriate in this sentence.
Nevertheless, I will not use one.
If these adverbs appear in the middle of a sentence, they are followed and preceded by a comma. As in the second of the two examples below, if a semicolon separates the two sentences and the second sentence starts with an adverb, this adverb is preceded by a semicolon and followed by a comma.
In this sentence, furthermore, commas would also be called for.
This sentence is a bit different; however, a comma is necessary as well.
Using commas to offset certain adverbs is optional, includingthen,so,yet,instead, andtoo (meaningalso).
So, that's it for this rule. or
So that's it for this rule.
A comma would be appropriate in this sentence, too. or
A comma would be appropriate in this sentence too.
Commas are often used to encloseparenthetical words and phrases within a sentence (i.e., information that is not essential to the meaning of the sentence). Such phrases are both preceded and followed by a comma, unless that would result in a doubling of punctuation marks or the parenthetical is at the start or end of the sentence. The following are examples of types of parenthetical phrases:
Introductory phrase:Once upon a time, my father ate a muffin.[16]
Interjection:My father ate the muffin, gosh darn it!
Aside:My father, if you don't mind me telling you this, ate the muffin.
Appositive:My father, a jaded and bitter man, ate the muffin.
Absolute phrase:My father, his eyes flashing with rage, ate the muffin.
Free modifier:My father, chewing with unbridled fury, ate the muffin.
Resumptive modifier:My father ate the muffin, a muffin which no man had yet chewed.
Summative modifier:My father ate the muffin, a feat which no man had attempted.
The parenthesization of phrases may change the connotation, reducing or eliminatingambiguity. In the following example, the thing in the first sentence thatis relaxing is the cool day, whereas in the second sentence, it is the walk since the introduction of commas makes "on a cool day" parenthetical:
They took a walk on a cool day that was relaxing.
They took a walk, on a cool day, that was relaxing.
As more phrases are introduced, ambiguity accumulates, but when commas separateeach phrase, the phrases clearly become modifiers of just one thing. In thesecond sentence below, that thing isthe walk:
They took a walk in the park on a cool day that was relaxing.
They took a walk, in the park, on a cool day, that was relaxing.
A comma is used to separatecoordinate adjectives (i.e.,adjectives that directly and equally modify the following noun). Adjectives are considered coordinate if the meaning would be the same if their order were reversed or ifand were placed between them. For example:
The dull, incessant droning butthe cute little cottage.
The devious lazy red frog suggests there are lazy red frogs (one of which is devious), whilethe devious, lazy red frog does not carry this connotation.
Some writers precede quoted material that is the grammatical object of an active verb of speaking or writing with a comma, as inMr. Kershner says, "You should know how to use a comma." Quotations that follow and support an assertion are often preceded by acolon rather than a comma.
Other writers do not put a comma before quotations unless one would occur anyway. Thus, they would writeMr. Kershner says "You should know how to use a comma."
When a date is written as a month followed by a day followed by a year, a comma separates the day from the year: December 19, 1941. This style is common in American English. The comma is used to avoid confusing consecutive numbers: December 19 1941.Most style manuals, includingThe Chicago Manual of Style[17]and theAP Stylebook,[18]also recommend that the year be treated as a parenthetical, requiring a second comma after it:"Feb. 14, 1987, was the target date."
If just the month and year are given, no commas are used:[19] "Her daughter may return in June 2009 for the reunion."
When the day precedes the month, the month name separates the numeric day and year, so commas are not necessary to separate them: "TheRaid on Alexandria was carried out on 19 December 1941."
Commas are used to separate parts of geographical references, such as city and state (Dallas, Texas) or city and country (Kampala, Uganda). Additionally, most style manuals, includingThe Chicago Manual of Style[20]and theAP Stylebook,[21]recommend that the second element be treated as a parenthetical, requiring a second comma after:"The plane landed in Kampala, Uganda, that evening."[22]
Similar to the case in natural languages, commas are often used to delineate the boundary between multiplemathematical objects in a list (e.g.,). Commas are also used to indicate thecomma derivative of atensor.[26]
In representing large numbers, from the right side to the left, English texts usually use commas to separate each group of three digits in front of the decimal.[27] This is almost always done for numbers of six or more digits, and often for four or five digits but not in front of the number itself. However, in much of Europe, Southern Africa and Latin America,periods or spaces are used instead; the comma is used as adecimal separator, equivalent to the use in English of thedecimal point.[28] In India, the groups are two digits, except for the rightmost group, which is of three digits. In some styles, the comma may not be used for this purpose at all (e.g. in theSI writing style[29]); a space may be used to separate groups of three digits instead.
Commas are used when rewriting names to present the surname first, generally in instances of alphabetization by surname:Smith, John. They are also used before many titles that follow a name:John Smith, Ph.D.
It can also be used in regnal names followed by their occupation:Louis XIII, king of France and Navarre.
Similarly in lists that are presented with an inversion:socks, green: 3 pairs; socks, red: 2 pairs; tie, regimental: 1.
Commas may be used to indicate that a word, or a group of words, has been omitted,[30] as inThe cat was white; the dog, brown. (Here the comma replaceswas.)
In his 1785 essayAn Essay on Punctuation,Joseph Robertson advocated a comma between the subject and predicate of long sentences for clarity; however, this usage is regarded as an error in modern times.
The good taste of the present age, has not allowed us to neglect the cultivation of the English language.
Whoever is capable of forgetting a benefit, is an enemy to society.
Differences between American and British usage in placement of commas and quotation marks
The comma and thequotation mark can be paired in several ways.
In Great Britain and many other parts of the world, punctuation is usually placed within quotation marks only if it is part of what is being quoted or referred to:[31][32][33]
My mother gave me the nickname "Bobby Bobby Bob Bob Boy", which really made me angry.
In American English, the comma was commonly included inside a quotation mark:[31][32]
My mother gave me the nickname "Bobby Bobby Bob Bob Boy," which really made me angry.
During theSecond World War, the British carried the comma over into abbreviations. Specifically, "Special Operations, Executive" was written "S.O.,E.". Nowadays, even thefull stops are frequently discarded in British usage.[34]
Western European languages like German, French, Italian, Spanish, and Portuguese use the same comma as English, with similar spacing, though usage may be somewhat different. For instance, in Standard German, subordinate clauses are always preceded by commas.
There are also a number of comma-likediacritics with "COMMA" in their Unicode names that are not intended for use aspunctuation. A comma-like low quotation mark is also available (shown below; corresponding sets of raised single quotation marks and double-quotation marks are not shown).
There are various other Unicode characters that include commas or comma-like figures with other characters or marks, that are not shown in these tables.
Modern Greek uses the sameUnicode comma for itskómma (κόμμα)[35] and it is officiallyromanized as a Latin comma,[36] but it has additional roles owing to its conflation with the formerhypodiastole, a curvedinterpunct used to disambiguate certain homonyms. As such, the comma functions as asilent letter in a handful of Greek words, principally distinguishingό,τι (ó,ti, 'whatever') fromότι (óti, 'that').[35]
Theenumeration orideographic comma (U+3001、IDEOGRAPHIC COMMA) is used inChinese,[37]: 20 Japanese punctuation, and somewhat inKorean punctuation. In China and Korea, this comma (顿号;頓號;dùnhào) is usually only used to separate items in lists, while it is the more common form of comma in Japan (読点,tōten,lit.'clause mark').
In documents that mixJapanese andLatin scripts, thefull-width comma (U+FF0C，FULLWIDTH COMMA) is used; this is the standard form of comma (逗号;逗號) in China. Since East Asian typography permits commas to join dependent clauses dealing with certain topics or lines of thought, commas may be used in ways that would be consideredcomma splices in English.[clarification needed]
The comma in theArabic script used by languages includingArabic,Urdu, andPersian, is "upside-down"⟨،⟩ (U+060C،ARABIC COMMA), in order to distinguish it from theArabic diacriticḍammah⟨ُ⟩ representing the vowel/u/, which is similarly shaped.[40] In Arabic texts, the Western-styled comma (٫) is used as adecimal point.
In many computer languages commas are used as a field delimiter to separate arguments to afunction,[42] to separate elements in alist, and to perform data designation on multiple variables at once.
In theC programming language the comma symbol is anoperator which evaluates its firstargument (which may have side-effects) and then returns the value of its evaluated second argument. This is useful inforstatements andmacros.
The comma is used as adiacritic mark inRomanian under⟨s⟩ (⟨Ș⟩,⟨ș⟩), and under⟨t⟩ (⟨Ț⟩,⟨ț⟩). Acedilla is occasionally used instead of it, but this is technically incorrect. The symbol⟨d̦⟩ ('d with comma below') was used as part of theRomanian transitional alphabet (19th century) to indicate the sounds denoted by the Latin letter⟨z⟩ or letters⟨dz⟩, where derived from aCyrillic ѕ (⟨ѕ⟩,/dz/). The comma and the cedilla are both derivative of⟨ʒ⟩ (a small cursive⟨z⟩) placed below the letter. From this standpoint alone,⟨ș⟩,⟨ț⟩, and⟨d̦⟩ could potentially be regarded as stand-ins for /sz/, /tz/, and /dz/ respectively.
InLatvian, the comma is used on the letters⟨ģ⟩,⟨ķ⟩,⟨ļ⟩,⟨ņ⟩, and historically also⟨ŗ⟩, to indicatepalatalization. Because the lowercase letter⟨g⟩ has adescender, the comma is rotated 180° and placed over the letter. Although theirAdobeglyph names are 'letter with comma', their names in theUnicode Standard are 'letter with a cedilla'. They were introduced to the Unicode standard before 1992 and, per Unicode Consortium policy, their names cannot be altered. In the late 1920s and 1930s, theLatgalian orthography used in Siberia used additional letters with comma:⟨c̦⟩,⟨d̦⟩,⟨m̦⟩,⟨p̦⟩,⟨ș⟩,⟨ț⟩,⟨v̦⟩,⟨z̦⟩.[43]
InLivonian, whose alphabet is based on a mixture of Latvian andEstonian alphabets, the comma is used on the letters⟨ḑ⟩,⟨ļ⟩,⟨ņ⟩,⟨ŗ⟩,⟨ț⟩ to indicate palatalization in the same fashion as Latvian, except that Livonian uses⟨ḑ⟩ and⟨ț⟩ to represent the samepalatalplosive phonemes which Latvian writes as⟨ģ⟩ and⟨ķ⟩ respectively.
InCzech andSlovak, the diacritic in the characters⟨ď⟩,⟨ť⟩, and⟨ľ⟩ resembles a superscript comma, but it is used instead of acaron because the letter has anascender. Other ascender letters with carons, such as letters⟨ȟ⟩ (used inFinnish Romani andLakota) and⟨ǩ⟩ (used inSkolt Sami), did not modify their carons to superscript commas.
In 16th-centuryGuatemala, the archaic lettercuatrillo with a comma (⟨Ꜯ⟩ and⟨ꜯ⟩) was used to write Mayan languages.[44]
^Swan, Michael (2006).Practical English Usage. Oxford University Press.
^Strunk, William (May 2007).The Elements of Style. Filiquarian Publishing. p. 12.ISBN978-1-59986-933-9.Do not join independent clauses by a comma.
^Garner's Modern American Usage, (Oxford: 2003, p. 655)
^Chicago Manual of Style:"It's conventional to put a comma after the year. The commas are like parentheses here, so it doesn't make sense to have only one."
^"Ask the Editor".AP Stylebook. 3 December 2008. Archived fromthe original on 4 December 2008. Retrieved7 June 2019.When a phrase refers to a month, day and year, set off the year with commas...Feb. 14, 1987, was the target date.
^"Mary traveled to Seattle, Washington, before going on to California.""FAQ item: Commas".The Chicago Manual of Style Online.Archived from the original on 20 May 2021. Retrieved20 May 2021.
^"Acme Pens was founded in Padua, Italy, in 2004.""Ask the Editor".AP Stylebook. Archived fromthe original on 4 December 2008. Retrieved29 October 2008.
^Reinders, Eric (2024).Reading Tolkien in Chinese: Religion, Fantasy, and Translation. Perspectives on Fantasy series. London, UK:Bloomsbury Academic.ISBN9781350374645.
^AbiFarès, Huda Smitshuijzen (2001).Arabic Typography: A Comprehensive Sourcebook. London: Saqi Books. p. 106.ISBN978-0-86356-347-8.The comma used in Arabic script is not only a mirror image of its Latin counterpart, but its tail is also turned upwards in order to avoid any possibility of confusing it with theDammah, theu short vowel mark.
