The full stop (Commonwealth English), period (North American English) or full point is a punctuation mark. It is used for several purposes, the most frequent of which is to mark the end of a declaratory sentence (as opposed to a question or exclamation); this sentence-terminal use is properly, or the precise meaning of, full stop.
The full stop is also often used alone to indicate omitted characters, or in an ellipsis, "..." to indicate omitted words. It may be placed after an initial letter used to stand for a name, or sometimes after each individual letter in an initialism or acronym, for example, "U.S.A."; however, this style is declining, and many initialisms like UK or NATO have individually become accepted norms. A full stop is also frequently used at the end of word abbreviations – in British usage, primarily truncations like Rev., but not after contractions like Revd; however, in American English it is used in both cases.
The full point also has multiple contexts in mathematics and computing, where it may be called a point (short for decimal point) or a dot. The full point glyph is sometimes called a baseline dot because, typographically, it is a dot on the baseline. This term distinguishes it from the interpunct (a raised dot). While full stop technically only applies to the full point when used to terminate a sentence, the distinction – drawn since at least 1897 – is not maintained by all modern style guides and dictionaries.
The full stop symbol derives from the Greek punctuation introduced by Aristophanes of Byzantium in the 3rd century BC. In his system, there were a series of dots whose placement determined their meaning. The full stop at the end of a completed thought or expression was marked by a high dot ⟨˙⟩, called the stigmḕ teleía (στιγμὴ τελεία) or "terminal dot". The "middle dot" ⟨·⟩, the stigmḕ mésē (στιγμὴ μέση), marked a division in a thought occasioning a longer breath (essentially a semicolon) and the low dot ⟨.⟩, called the hypostigmḕ (ὑποστιγμή) or "underdot", marked a division in a thought occasioning a shorter breath (essentially a comma). In practice, scribes mostly employed the terminal dot; the others fell out of use and were later replaced by other symbols. From the 9th century, the full stop began appearing as a low mark instead of a high one; by the advent of printing in Western Europe, the low mark was regular and then universal.
The name period is first attested (as the Latin loanword peridos) in Ælfric of Eynsham's Old English treatment on grammar. There, it is distinguished from the full stop (the distinctio) and continues the Greek underdot's earlier function as a comma between phrases. It shifted its meaning to a dot marking a full stop in the works of the 16th-century grammarians. In 19th-century texts, both British English and American English were consistent in their usage of the terms period and full stop. The word period was used as a name for what printers often called the "full point" or the punctuation mark that was a dot on the baseline and used in several situations. The phrase full stop was only used to refer to the punctuation mark when it was used to terminate a sentence. This distinction seems to be eroding. For example, the 1998 edition of Fowler's Modern English Usage used full point for the character after an abbreviation, but full stop or full point at the end of a sentence; while the 2015 edition treats them as synonymous (and prefers full stop), and New Hart's Rules does likewise (but prefers full point). The last edition (1989) of the original Hart's Rules exclusively used full point.
Full stops indicate the end of sentences that are not questions or exclamations.
A full stop is used after some abbreviations. If the abbreviation ends a declaratory sentence there is no additional period immediately following the full stop that ends the abbreviation (e.g. "My name is Gabriel Gama, Jr."). Though two full stops (one for the abbreviation, one for the sentence ending) might be expected, conventionally only one is written. This is an intentional omission, and thus not haplography, which is unintentional omission of a duplicate. In the case of an interrogative or exclamatory sentence ending with an abbreviation, a question or exclamation mark can still be added (e.g. "Are you Gabriel Gama, Jr.?").
Abbreviations and personal titles of address
According to the Oxford A–Z of Grammar and Punctuation, "If the abbreviation includes both the first and last letter of the abbreviated word, as in 'Mister' ['Mr'] and 'Doctor' ['Dr'], a full stop is not used."[better source needed] This does not include, for example, the standard abbreviations for titles such as Professor ("Prof.") or Reverend ("Rev."), because they do not end with the last letter of the word they are abbreviating.
Acronyms and initialisms
In acronyms and initialisms, the modern style is generally to not use full points after each initial (e.g.: DNA, UK, USSR). The punctuation is somewhat more often used in American English, most commonly with U.S. and U.S.A. in particular. However, this depends much upon the house style of a particular writer or publisher. As some examples from American style guides, The Chicago Manual of Style (primarily for book and academic-journal publishing) deprecates the use of full points in acronyms, including U.S., while The Associated Press Stylebook (primarily for journalism) dispenses with full points in acronyms except for certain two-letter cases, including U.S., U.K., and U.N., but not EU.
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The period glyph is used in the presentation of numbers, but in only one of two alternate styles at a time.
In the more prevalent usage in English-speaking countries, the point it represents a decimal separator, visually dividing whole numbers from fractional (decimal) parts. The comma is then used to separate the whole-number parts into groups of three digits each, when numbers are sufficiently large.
- 1.007 (one and seven thousandths)
- 1,002.007 (one thousand two and seven thousandths)
- 1,002,003.007 (one million two thousand three and seven thousandths)
The more prevalent usage in much of Europe, southern Africa, and Latin America (with the exception of Mexico due to the influence of the United States), reverses the roles of the comma and point, but sometimes substitutes a space for a point.
- 1,007 (one and seven thousandths)
- 1.002,007 or 1 002,007 (one thousand two and seven thousandths)
- 1.002.003,007 or 1 002 003,007 (one million two thousand three and seven thousandths)
India, Bangladesh, Nepal, and Pakistan follow the Indian numbering system, which utilizes commas and decimals much like the aforementioned system popular in most English-speaking countries, but separates values of one hundred thousand and above differently, into divisions of lakh and crore:
- 1.007 (one and seven thousandths)
- 1,002.007 (one thousand two and seven thousandths)
- 10,02,003.007 (one million two thousand three and seven thousandths or ten lakh two thousand three and seven thousandths)
In countries that use the comma as a decimal separator, the point is sometimes found as a multiplication sign; for example, 5,2 . 2 = 10,4; this usage is impractical in cases where the point is used as a decimal separator, hence the use of the interpunct: 5.2 · 2 = 10.4. This notation is also seen when multiplying units in science; for example, 50 km/h could be written as 50 km·h−1. However, the point is used in all countries to indicate a dot product, i.e. the scalar product of two vectors.
It is used in many programming languages as an important part of the syntax. C uses it as a means of accessing a member of a struct, and this syntax was inherited by C++ as a means of accessing a member of a class or object. Java and Python also follow this convention. Pascal uses it both as a means of accessing a member of a record set (the equivalent of struct in C), a member of an object, and after the end construct that defines the body of the program. In APL it is also used for generalised inner product and outer product. In Erlang, Prolog, and Smalltalk, it marks the end of a statement ("sentence"). In a regular expression, it represents a match of any character. In Perl and PHP, the dot is the string concatenation operator. In the Haskell standard library, it is the function composition operator. In COBOL a full stop ends a statement.
In file systems, the dot is commonly used to separate the extension of a file name from the name of the file. RISC OS uses dots to separate levels of the hierarchical file system when writing path names—similar to
/ (forward-slash) in Unix-based systems and
\ (back-slash) in MS-DOS-based systems and the Windows NT systems that succeeded them.
Bourne shell-derived command-line interpreters, such as sh, ksh, and bash, use the dot as a command to read a file and execute its content in the running interpreter. (Some of these also offer source as a synonym, based on that usage in the C-shell.)
The term STOP was used in telegrams in place of the full stop. The end of a sentence would be marked by STOP; its use "in telegraphic communications was greatly increased during the World War, when the Government employed it widely as a precaution against having messages garbled or misunderstood, as a result of the misplacement or emission of the tiny dot or period."
In British English, the words "full stop" at the end of an utterance strengthen it, it admits of no discussion: "I'm not going with you, full stop." In American English the word "period" serves this function.
Punctuation styles when quoting
The practice in the United States and Canada is to place full stops and commas inside quotation marks in most styles. In the British system, which is also called "logical quotation", full stops and commas are placed according to grammatical sense: This means that when they are part of the quoted material, they should be placed inside, and otherwise should be outside. For example, they are placed outside in the cases of words-as-words, titles of short-form works, and quoted sentence fragments.
- Bruce Springsteen, nicknamed "the Boss," performed "American Skin." (American style)
- Bruce Springsteen, nicknamed "the Boss", performed "American Skin". (logical or British style)
- He said, "I love music." (both)
There is some national crossover. American style is common in British fiction writing. British style is sometimes used in American English. For example, the Chicago Manual of Style recommends it for fields where comma placement could affect the meaning of the quoted material, such as linguistics and textual criticism.
Use of placement according to logical or grammatical sense, or "logical convention", now the more common practice in regions other than North America, was advocated in the influential book The King's English by Fowler and Fowler, published in 1906. Prior to the influence of this work, the typesetter's or printer's style, or "closed convention", now also called American style, was common throughout the world.
Spacing after a full stop
There have been a number of practices relating to the spacing after a full stop. Some examples are listed below:
- One word space ("French spacing"). This is the current convention in most countries that use the ISO basic Latin alphabet for published and final written work, as well as digital media.
- Two word spaces ("English spacing"). It is sometimes claimed that the two-space convention stems from the use of the monospaced font on typewriters, but in fact that convention replicates much earlier typography — the intent was to provide a clear break between sentences. This spacing method was gradually replaced by the single space convention in published print, where space is at a premium, and continues in much digital media.
- One widened space (such as an em space). This spacing was seen in historical typesetting practices (until the early 20th century). It has also been used in other typesetting systems such as the Linotype machine and the TeX system. Modern computer-based digital fonts can adjust the spacing after terminal punctuation as well, creating a space slightly wider than a standard word space.
Full stops in other scripts
Although the present Greek full stop (τελεία, teleía) is romanized as a Latin full stop and encoded identically with the full stop in Unicode, the historic full stop in Greek was a high dot and the low dot functioned as a kind of comma, as noted above. The low dot was increasingly but irregularly used to mark full stops after the 9th century and was fully adapted after the advent of print. The teleia should also be distinguished from the ano teleia mark, which is named "high stop" but looks like an interpunct (a middle dot) and principally functions as the Greek semicolon.
In some East Asian languages, notably Chinese and Japanese, a small circle is used instead of a solid dot: "。" (U+3002 "Ideographic Full Stop", simplified Chinese: 句号, traditional Chinese: 句號, Japanese: 句点). Notably, in Taiwan, Hong Kong, and Macao usage, the full stop is written at center height instead of on the line.
In the Devanagari script, used to write Hindi and Sanskrit among other Indian languages, a vertical line ("।") (U+0964 "Devanagari Danda") is used to mark the end of a sentence. It is known as poorna viraam (full stop) in Hindi, and Daa`ri in Bengali. Some Indian languages also use the full stop, such as Marathi. In Tamil, it is known as mutrupulli, which means end dot.
In Sinhala, it is known as kundaliya: "෴" ((U+0DF4) symbol "full stop"). Periods were later introduced into Sinhala script after the introduction of paper due to the influence of Western languages. See also Sinhala numerals.
Urdu uses the "۔" (U+06D4) symbol.
In Thai, no symbol corresponding to the full stop is used as terminal punctuation. A sentence is written without spaces, and a space is typically used to mark the end of a clause or sentence.
In the Ge'ez script used to write Amharic and several other Ethiopian and Eritrean languages, the equivalent of the full stop following a sentence is the ˈarat nettib "።"—which means four dots. The two dots on the right are slightly ascending from the two on the left, with space in between.
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The character is encoded at U+002E . FULL STOP (HTML
In text messages
Researchers from Binghamton University performed a small study, published in 2016, on young adults and found that text messages that included sentences ended with full stops—as opposed to those with no terminal punctuation—were perceived as insincere, though they stipulated that their results apply only to this particular medium of communication: "Our sense was, is that because [text messages] were informal and had a chatty kind of feeling to them, that a period may have seemed stuffy, too formal, in that context," said head researcher Cecelia Klin. The study did not find handwritten notes to be affected.
A 2016 story by Jeff Guo in The Washington Post, stated that the line break had become the default method of punctuation in texting, comparable to the use of line breaks in poetry, and that a period at the end of a sentence causes the tone of the message to be perceived as cold, angry or passive-aggressive.
According to Gretchen McCulloch, an internet linguist, using a full stop to end messages is seen as "rude" by more and more people. She said this can be attributed to the way we text and use instant messaging apps like WhatsApp and Facebook Messenger. She added that the default way to break up one's thoughts is to send each thought as an individual message. 
- Williamson, Amelia A. "Period or Comma? Decimal Styles over Time and Place" (PDF). Science Editor. 31 (2): 42–43. Archived from the original (PDF) on February 28, 2013. Retrieved 21 September 2013.
- Truss, Lynn (2004). Eats, Shoots & Leaves: The Zero Tolerance Approach to Punctuation. New York: Gotham Books. p. 25. ISBN 1-59240-087-6.
- "The Punctuation Points". American Printer and Lithographer. 24 (6): 278. August 1897. Retrieved 24 December 2013.
- Nicolas, Nick. "Greek Unicode Issues: Punctuation Archived August 6, 2012, at Archive.today". 2005. Accessed 7 Oct 2014.
- Oxford English Dictionary, 3rd ed. "period, n., adj., and adv." Oxford University Press, 2005,
- "The Workshop: Printing for Amateurs". The Bazaar, Exchange and Mart, and Journal of the Household. 13: 333. 6 November 1875. Retrieved 24 December 2013.
- Burchfield, R. W. (2010) . "full stop". Fowler's Modern English Usage (Revised 3rd ed.). Oxford University Press. pp. 317–318. ISBN 978-0-19-861021-2.
- Butterfield, Jeremy (2015). "full stop". Fowler's Dictionary of Modern English Usage (4th ed.). Oxford University Press. pp. 331–332. ISBN 978-0-19-966135-0.
- Waddingham, Anne (2014). "4.6: Full point". New Hart's Rules (2nd ed.). Oxford University Press. p. 81. ISBN 978-0-19-957002-7. Essentially the same text is found in the previous edition under various titles, including New Hart's Rules, Oxford Style Manual, and The Oxford Guide to Style.
- Hart, Horace; et al. (1989) . Hart's Rules for Compositors and Readers (Corrected 39th ed.). Oxford University Press. pp. 2–5, 41, etc. ISBN 0-19-212983-X.
- A Comparison of the Frequency of Number/Punctuation and Number/Letter Combinations in Literary and Technical Materials
- Charles F. Meyer (1987). A Linguistic Study of American Punctuation. Peter Lang Publishing, Incorporated. ISBN 978-0-8204-0522-3., referenced in Frequencies for English Punctuation Marks Archived 2 November 2013 at the Wayback Machine
- Cindy Barden Grammar, Grades 4–5 2007 p9 "Use a period after a person's initials. Examples: A. A. Milne L.B.Peep W157 Use Periods With Initials Name. Initials are abbreviations for parts of a person's name. Date: Add periods at the ends of sentences, after abbreviations, and after initials".
- The Brief Thomson Handbook David Blakesley, Jeffrey Laurence Hoogeveen – 2007 -p477 "Use periods with initials: George W. Bush Carolyn B. Maloney
- New Hart's Rules: The handbook of style for writers and editors. Oxford University Press, 2005. 2005. ISBN 0-19-861041-6.
- Oxford A–Z of Grammar and Punctuation by John Seely.
- "Punctuation in abbreviations". OxfordDictionaries.com. Oxford University Press. 2017. "Punctuation" section. Retrieved 11 October 2017.
- "Initialisms". OxfordDictionaries.com. Oxford University Press. 2017. "Abbreviations" section. Retrieved 11 October 2017.
- The Chicago Manual of Style, 16th ed.
- "abbreviations and acronyms". The Associated Press Stylebook. 2015. pp. 1–2.
- Ross, Nelson (1928). "HOW TO WRITE TELEGRAMS PROPERLY". The Telegraph Office. Retrieved 11 June 2018.
- Lee, Chelsea (2011). "Punctuating Around Quotation Marks". Style Guide of the American Psychological Association. Retrieved 25 October 2011.
- "Style Guide" (PDF). Journal of Irish and Scottish Studies. Research Institute of Irish and Scottish Studies, University of Aberdeen. 2008. Archived from the original (PDF) on 10 April 2011. Retrieved 2015-09-15.
Punctuation marks are placed inside the quotation marks only if the sense of the punctuation is part of the quotation; this system is referred to as logical quotation.
- Scientific Style and Format: The CBE Manual for Authors, Editors and Publishers (PDF). Cambridge University Press. 2002. ISBN 9780521471541. Retrieved 4 September 2015.
In the British style (OUP 1983), all signs of punctuation used with words and quotation marks must be placed according to the sense.
- Butcher, Judith; et al. (2006). Butcher's Copy-editing: The Cambridge Handbook for Editors, Copy-editors and Proofreaders. Cambridge University Press. p. 273. ISBN 978-0-521-84713-1.
- Wilbers, Stephen. "Frequently Asked Questions Concerning Punctuation". Retrieved 10 September 2015.
The British style is strongly advocated by some American language experts. In defense of nearly a century and a half of the American style, however, it may be said that it seems to have been working fairly well and has not resulted in serious miscommunication. Whereas there clearly is some risk with question marks and exclamation points, there seems little likelihood that readers will be misled concerning the period or comma. There may be some risk in such specialized material as textual criticism, but in that case author and editors may take care to avoid the danger by alternative phrasing or by employing, in this exacting field, the exacting British system. In linguistic and philosophical works, specialized terms are regularly punctuated the British way, along with the use of single quotation marks. [quote attributed to Chicago Manual of style, 14th ed.]
- Chicago Manual of Style (15th ed.). University of Chicago Press. 2003. pp. 6.8 , – 6.10. ISBN 0-226-10403-6.
According to what is sometimes called the British style (set forth in The Oxford Guide to Style [the successor to Hart's Rules]; see bibliog. 1.1.]), a style also followed in other English-speaking countries, only those punctuation points that appeared in the original material should be included within the quotation marks; all others follow the closing quotation marks. … In the kind of textual studies where retaining the original placement of a comma in relation to closing quotation marks is essential to the author's argument and scholarly integrity, the alternative system described in 6.10 ['the British style'] could be used, or rephrasing might avoid the problem.
- Weiss, Edmond H. (2015). The Elements of International English Style: A Guide to Writing Correspondence, Reports, Technical Documents Internet Pages For a Global Audience. M. E. Sharpe. p. 75. ISBN 978-0-7656-2830-5. Retrieved 24 January 2016.
- Einsohn, Amy (2006). The Copyeditor's Handbook: A Guide for Book Publishing and Corporate Communications (2nd ed.). Berkeley, Los Angeles, London: University of California Press. p. 113. ISBN 978-0-520-24688-1.
- Manjoo, Farhad (January 13, 2011). "Space Invaders". Slate.
- Heraclitus (1 November 2011). "Why two spaces after a period isn't wrong".
- Felici, James (2003). The Complete Manual of Typography: A Guide to Setting Perfect Type. Berkeley, CA: Peachpit Press. p. 80. ISBN 0-321-12730-7.; Bringhurst, Robert (2004). The Elements of Topographic Style (3.0 ed.). Washington and Vancouver: Hartley & Marks. p. 28. ISBN 0-88179-206-3.
- See for example, University of Chicago Press (1911). Manual of Style: A Compilation of Typographical Rules Governing the Publications of The University of Chicago, with Specimens of Types Used at the University Press (Third ed.). Chicago: University of Chicago. p. 101. ISBN 1-145-26446-8.
- Mergenthaler Linotype Company (1940). Linotype Keyboard Operation: Methods of Study and Procedures for Setting Various Kinds of Composition on the Linotype. Mergenthaler Linotype Company. ASIN B000J0N06M. cited in Simonson, Mark (5 March 2004). "Double-spacing after Periods". Typophile. Typophile. Retrieved 5 April 2010.
- Eijkhout, Victor (2008). "TeX by Topic, A TeXnician's Reference" (PDF). Lulu: 185–188. Cite journal requires
- Felici, James (2003). The Complete Manual of Typography: A Guide to Setting Perfect Type. Berkeley, CA: Peachpit Press. p. 80. ISBN 0-321-12730-7.; Fogarty, Mignon (2008). Grammar Girl's Quick and Dirty Tips for Better Writing (Quick and Dirty Tips). New York: Holt Paperbacks. p. 85. ISBN 978-0-8050-8831-1.; Straus, Jane (2009). The Blue Book of Grammar and Punctuation: An Easy-to-Use Guide with Clear Rules, Real-World Examples, and Reproducible Quizzes (10th ed.). San Francisco, CA: Jossey-Bass. p. 52. ISBN 978-0-470-22268-3.
- Ελληνικός Οργανισμός Τυποποίησης [Ellīnikós Organismós Typopoíīsīs, "Hellenic Organization for Standardization"]. ΕΛΟΤ 743, 2η Έκδοση [ELOT 743, 2ī Ekdosī, "ELOT 743, 2nd ed."]. ELOT (Athens), 2001. (in Greek).
- ta:முற்றுப்புள்ளி (தமிழ் நடை)
- Lunde, Ken (2009). CJKV Information Processing. O'Reilly. pp. 502–505. ISBN 9780596514471.
- "You Should Watch The Way You Punctuate Your Text Messages – Period". National Public Radio. 2015-12-20. Retrieved 2015-12-20.
- Gunraj, Danielle; Drumm-Hewitt, April; Dashow, Erica; Upadhyay, Sri Siddhi; Klim, Celia (February 2016) , "Texting insincerely: The role of the period in text messaging", Computers in Human Behavior, 55: 1067–1075, doi:10.1016/j.chb.2015.11.003
- Guo, Jeff (June 13, 2016). "Stop. Using. Periods. Period.". The Washington Post.
- Morton, Becky (August 2019). "Is the full stop rude?". BBC News.