Editing Abbreviation (section)

== Style conventions in English ==

In modern English, there are multiple conventions for abbreviation, and there is controversy as to which should be used. One generally accepted rule is to be consistent in a body of work. To this end, publishers may express their preferences in a [[style guide]].

Some controversies that arise are described below.

=== Capitalization ===

If the original word was capitalized then the first letter of its abbreviation should retain the capital, for example Lev. for ''Leviticus''. When a word is abbreviated to more than a single letter and was originally spelled with lower case letters then there is no need for capitalization. However, when abbreviating a phrase where only the first letter of each word is taken, then all letters should be capitalized, as in YTD for ''year-to-date'', PCB for ''printed circuit board'' and FYI for ''for your information''. However, see the following section regarding abbreviations that have become common vocabulary: these are no longer written with capital letters.

=== Periods ===
[[File:“To Penna. R.R. Station”.jpg|thumb|Sign in New York City subway, reading "Penna." for Penn''sylvani''a, showing American style of including the period even for contractions]]
A period (a.k.a. full stop) is sometimes used to signify abbreviation, but opinion is divided as to when and if this convention is best practice.

According to [[Hart's Rules]], a word shortened by dropping letters from the end terminates with a period, whereas a word shorted by dropping letters from the middle does not.<ref name=harts/>{{rp|p167–170}} [[Fowler's Modern English Usage]] says a period is used for both of these shortened forms, but recommends against this practice: advising it only for end-shortened words and lower-case initialisms; not for middle-shortened words and upper-case initialisms.<ref>{{cite book|title=Pocket Fowler's Modern English Usage|edition=2nd|editor-first=Robert|editor-last=Allen|publisher=Oxford University Press|date=2008|isbn=9780191727078|contribution=Full stop}}</ref>

{| class="wikitable"
|-
!Full form
!Shortening
!Short form
!Source
|-
|[[Doctor (title)|Doctor]]
|mid
|Dr
|D——r
|-
|[[Professor]]
|end
|Prof.
|Prof...
|-
|[[Reverend|The Reverend]]
|end
|Rev.
|Rev...
|-
|[[Reverend|The Reverend]]
|mid
|Revd
|Rev——d
|-
|[[The Right Honourable]]
|mid and end
|Rt Hon.
|R——t Hon...
|}

Some British style guides, such as for [[The Guardian]] and [[The Economist]], disallow periods for all abbreviations.<ref>{{Cite news |date=2021-04-30 |title=Guardian and Observer style guide: A |language=en-GB |work=The Guardian |url=https://www.theguardian.com/guardian-observer-style-guide-a |access-date=2023-04-22 |issn=0261-3077 |quote="Do not use full points in abbreviations, or spaces between initials, including those in proper names: IMF, mph, eg, 4am, M&S, No 10, AN Wilson, WH Smith, etc." }}</ref><ref>{{cite book |author=The Economist |title=Style guide |date=2005 |publisher=Profile Books |edition=9th |isbn=978-1-84765-030-6 |location=London |oclc=236346040 |page=117 |quote=Do not use full stops in abbreviations... }}</ref>

In [[American English]], the period is usually included regardless of whether or not it is a contraction, e.g. ''Dr.'' or ''Mrs.'' In some cases, periods are optional, as in either ''US'' or ''U.S.'' for ''United States'', ''EU'' or ''E.U.'' for ''European Union'', and ''UN'' or ''U.N.'' for ''United Nations''. There are some house styles, however—American ones included—that remove the periods from almost all abbreviations. For example:
* The U.S. [[Manual on Uniform Traffic Control Devices]] advises that periods should not be used with abbreviations on road signs, except for cardinal directions as part of a destination name. (For example, ''"Northwest Blvd"'', ''"W. Jefferson"'', and ''"PED XING"'' all follow this recommendation.) 
* [[AMA Manual of Style|AMA style]], used in many [[medical journal]]s, uses no periods in abbreviations or acronyms, with almost no exceptions. Thus [[exempli gratia|eg]], [[id est|ie]], [[wikt:versus|vs]], [[et al.]], [[Doctor (title)|Dr]], [[Mr.|Mr]], [[magnetic resonance imaging|MRI]], [[intensive care unit|ICU]], and hundreds of others contain no periods. The only exceptions are {{char|No.}} (an abbreviation of [[Numero sign|Numero]], Number), to avoid confusion with the word "[[Yes and no|No]]"; initials within persons' names (such as "George R. Smith"); and "St." within persons' names when the person prefers it (such as "Emily R. St. Clair") (but not in city names such as ''St Louis'' or ''St Paul'').

Acronyms that were originally capitalized (with or without periods) but have since entered the vocabulary as generic words are no longer written with capital letters nor with any periods. Examples are [[sonar]], [[radar]], [[lidar]], [[laser]], [[SNAFU|snafu]], and [[Scuba set|scuba]].

When an abbreviation appears at the end of a sentence, only one period is used: ''The capital of the United States is Washington, D.C.''

In the past, some initialisms were styled with a period after each letter and a space between each pair. For example, ''U.&nbsp;S.'', but today this is typically ''US''.

=== Plural ===

There are multiple ways to pluralize an abbreviation. Sometimes this accomplished by adding an apostrophe and an ''s'' ({{char|'s}}), as in "two PC's have broken screens". But, some find this confusing since the notation can indicate [[possessive case]]. And, this style is deprecated by many style guides. For instance, [[Kate Turabian]], writing about style in academic writings,<ref name="Chicago">{{cite book|last=Turabian |first = Kate L.|title =[[A Manual for Writers of Research Papers, Theses, and Dissertations]] | edition = 7th | at=subsection 20.1.2| publisher = University of Chicago Press | author-link=Kate L. Turabian}}</ref> allows for an apostrophe to form plural acronyms "only when an abbreviation contains internal periods or both capital and lowercase letters". For example, "DVDs" and "URLs" and "Ph.D.'s", while the [[Modern Language Association]]<ref name="MLA">Modern Language Association (MLA) Handbook for Writers of Research Papers, 7th Edition 2009, subsection 3.2.7.g</ref> explicitly says, "do not use an apostrophe to form the plural of an abbreviation". Also, the [[American Psychological Association]] specifically says,<ref name="APA">Publication Manual of the American Psychological Association (APA), 5th Edition 2001, subsection 3.28</ref><ref name=autogenerated1>''Publication Manual of the American Psychological Association'', 6th Edition 2010, subsection 4.29</ref> "without an apostrophe".

However, the 1999 style guide for ''[[The New York Times]]'' states that the addition of an apostrophe is necessary when pluralizing all abbreviations, preferring "PC's, TV's and VCR's".<ref>Siegal, AM., Connolly, WG., [https://books.google.com/books?id=RT5w0s7_op8C&q=plurals+abbreviations ''The New York Times Manual of Style and Usage''], Three Rivers Press, 1999, p. 24.</ref>

Forming a plural of an initialization without an apostrophe can also be used for a number, or a letter. Examples:<ref>{{cite book|last=Garner|first=Bryan|title=Garner's Modern American Usage|year=2009|publisher=Oxford University Press|location=Oxford; New York|isbn=978-0-19-538275-4|page=638}}</ref>
* [[run batted in|Runs batted in]], RBIs
* The roaring 20s
* Mind your Ps and Qs

For units of measure, the same form is used for both singular and plural. Examples:

* 1&nbsp;lb or 20&nbsp;lb
* 1&nbsp;ft or 16&nbsp;ft
* 1&nbsp;min or 45&nbsp;min

When an abbreviation contains more than one period, ''Hart's Rules'' recommends putting the ''s'' after the final one. Examples:

* Ph.D.s
* M.Phil.s
* The d.t.s

However, the same plurals may be rendered less formally as:

* PhDs
* MPhils
* The DTs (This is the recommended form in the ''New Oxford Dictionary for Writers and Editors''.)

According to ''Hart's Rules'', an apostrophe may be used in rare cases where clarity calls for it, for example when letters or symbols are referred to as objects.
* The x's of the equation
* Dot the i's and cross the t's
However, the apostrophe can be dispensed with if the items are set in italics or quotes:
* The ''x''s of the equation
* Dot the 'i's and cross the 't's

In Latin, and continuing to the derivative forms in European languages as well as English, single-letter abbreviations had the plural being a doubling of the letter for note-taking. Most of these deal with writing and publishing. A few longer abbreviations use this as well.

{| class="wikitable"
|-
!Singular abbreviation
!Word/phrase
!Plural abbreviation
!Discipline
|-
|d.
| didot
|dd.
| typography
|-
|f.
| following line or page
|ff.
|notes
|-
|F.
| folio
|Ff.
|literature
|-
|h.
| hand
|hh.
| horse height
|-
|J.
| Justice
|JJ.
|law (job title)
|-
|l.
| line
|ll.
|notes
|-
|MS
| manuscript
|MSS
|notes
|-
|op.
| opus (plural: opera)
|opp.
|notes
|-
|p.
|page
|pp.
|notes
|-
|Q.
| quarto
|Qq.
|literature
|-
|s. (or [[§]])
|section
|ss. (or §§)
|notes
|-
|v.
|volume
|vv.
|notes
|}

=== Conventions followed by publications and newspapers ===

==== United States ====

Publications based in the U.S. tend to follow the style guides of ''[[The Chicago Manual of Style]]'' and the [[Associated Press]].<ref>{{Cite web |title=The Chicago Manual of Style, explained {{!}} University of Chicago News |url=https://news.uchicago.edu/explainer/chicago-manual-style-explained |access-date=2024-06-23 |website=news.uchicago.edu |language=en}}</ref> The U.S. government follows a style guide published by the [[U.S. Government Printing Office]]. The [[National Institute of Standards and Technology]] sets the style for abbreviations of units.

==== United Kingdom ====

Many British publications follow some of these guidelines in abbreviation:
* For the sake of convenience, many British publications, including the [[BBC]] and ''[[The Guardian]]'', have completely done away with the use of periods in all abbreviations. These include:
** Social titles, e.g. Ms or Mr (though these would usually have not had periods—see above) Capt, Prof, ''etc.;''
** Two-letter abbreviations for countries (''"US"'', not ''"U.S."'');
** Abbreviations beyond three letters (full caps for all except initialisms{{clarify|date=November 2015}});
** Words seldom abbreviated with lower case letters (''"PR"'', instead of ''"p.r."'', or ''"pr"'')
** Names (''"FW de Klerk"'', ''"GB Whiteley"'', ''"Park JS"''). A notable exception is ''[[The Economist]]'' which writes ''"Mr F. W. de Klerk"''.
** Scientific units (see Measurements below).
* Acronyms are often referred to with only the first letter of the abbreviation capitalized. For instance, the [[North Atlantic Treaty Organization]] can be abbreviated as ''"Nato"'' or ''"NATO"'', and [[Severe Acute Respiratory Syndrome]] as ''"Sars"'' or ''"SARS"'' (compare with ''"[[laser]]"'' which has made the full transition to an English word and is rarely capitalised at all).
* Initialisms are always written in capitals; for example the ''"British Broadcasting Corporation"'' is abbreviated to ''"BBC"'', never ''"Bbc"''. An initialism is also an acronym but is not pronounced as a word.
* When abbreviating scientific units, no space is added between the number and unit (<nowiki>100mph, 100m, 10cm, 10°C</nowiki>). (This is contrary to the SI standard; see below.)

==== Miscellaneous and general rules ====

* A doubled letter appears in abbreviations of some Welsh names, as in [[Welsh language|Welsh]] the double "l" is a separate sound: "Ll. George" for (British prime minister) [[David Lloyd George]].
* Some titles, such as "Reverend" and "Honourable", are spelt out when preceded by "the", rather than as "Rev." or "Hon." respectively. This is true for most British publications, and some in the United States.
* A repeatedly used abbreviation should be spelt out for identification on its first occurrence in a written or spoken passage.<ref>[[Gary Blake]] and [[Robert W. Bly]], ''The Elements of Technical Writing'', pg. 53. New York City: Macmillan Publishers, 1993. {{ISBN|0020130856}}</ref> Abbreviations likely to be unfamiliar to many readers should be avoided.