Abbreviation

'''{{selfref|For guidelines on making and editing abbreviation articles on Wikipedia, see [[Wikipedia:Disambiguation and abbreviations]].}}
{{Unreferenced|date=January 2007}}
An '''abbreviation''' (from [[Latin]] ''brevis'' "short") is a shortened form of a [[word]] or [[phrase]]. Usually, but not always, it consists of a letter or group of letters taken from the word or phrase. For example, the word "abbreviation" can itself be represented by the abbreviation "abbr." or "abbrev."

== Types of abbreviations ==
Apart from the common form of shortening one word, there are other types of abbreviations. These include [[acronym and initialism]] (including [[three-letter acronym]]s), [[apocope]], [[clipping (phonetics)|clipping]], [[elision]], [[syncope]], syllabic abbreviation, and [[portmanteau]].

=== Syllabic abbreviation ===
:''Related article: [[Clipping (morphology)]]''
A syllabic abbreviation (SA) is an abbreviation formed from (usually) initial [[syllable]]s of several [[Word (linguistics)|words]], such as ''[[Interpol]]'' for '''''Inter'''national '''pol'''ice'', but should be distinguished from [[portmanteau]]x. They are usually written in [[lower case]], sometimes starting with a [[capital letter]], and are always [[pronunciation|pronounced]] as words rather than letter by letter.

==== Use in various languages ====
Syllabic abbreviations are not widely used in [[English language|English]] or [[French language|French]], but are common in certain languages, like [[German language|German]] and [[Russian Language|Russian]].

They prevailed in [[Nazi Germany|Germany under the Nazis]] and in the [[Soviet Union]] for naming the plethora of new bureaucratic organizations. For example, ''[[Gestapo]]'' stands for '''''Ge'''heime '''Sta'''ats-'''Po'''lizei'', or "secret state police". This has given syllabic abbreviations a negative connotation, even though they were used in Germany before the Nazis, such as ''[[:de:Schupo|Schupo]]'' for ''Schutzpolizist''. Even now Germans call part of their police ''[[Kripo]]'' for ''Kriminalpolizei''. Syllabic abbreviations were also typical of German language used in the [[German Democratic Republic]], for example, ''[[Stasi]]'' for ''Staatssicherheit'' ("state security", the secret police and secret service) or ''Vopo'' for ''Volkspolizist'' ("people's policeman").

Some syllabic abbreviations from [[Russian Language|Russian]] that are familiar to English speakers include [[samizdat]] and [[kolkhoz]]. The English names for the Soviet "[[Comintern]]" ('''Com'''munist '''Intern'''ational) and "[[Milrevcom]]" ('''Mil'''itary '''Rev'''olution '''Com'''mittee) are further examples.

[[George Orwell|Orwell's]] novel ''[[Nineteen Eighty-Four|1984]]'' uses fictional syllabic abbreviations like "Ingsoc" ('''Eng'''lish '''Soc'''ialism) to evoke the use of language under the Nazi and Soviet regimes.

[[East Asia]]n languages whose writing uses [[Chinese language|Chinese]]-originated [[ideogram]]s instead of an alphabet form abbreviations similarly by using key [[Chinese character|characters]] from a term or phrase. For example, in [[Japanese language|Japanese]] the term for the [[United Nations]], ''kokusai rengō'' (国際連合) is often abbreviated to ''kokuren'' (国連). Such abbreviations are called [[:ja:略語|ryakugo]] (略語) in Japanese. SAs are frequently used for names of universities: for instance, ''Beida'' (北大, Běidà) for [[Peking University]] ([[Beijing]]), ''Yondae'' (연대) for the [[Yonsei University]], ''Seouldae'' (서울대) for the [[Seoul National University]] and ''Tōdai'' (東大) for the [[University of Tokyo]].

==== Syllabic abbreviations in names of organizations ====

Syllabic abbreviations are preferred by the US [[Navy]] as it increases readability amidst the large number of [[initialism]]s that would otherwise have to fit into the same acronyms. Hence ''[[DESRON]] 6'' is used (in the full capital form) to mean "Destroyer Squadron 6," and COMNAVAIRLANT means "Commander, Naval Air Forces, Atlantic".

==Style conventions in English==

In [[modern English]] there are several conventions for abbreviations and the choice may be confusing. The only rule universally accepted is that one should be ''consistent,'' and to make this easier, publishers express their preferences in a [[style guide]]. Questions which arise include those in the following subsections.

=== Lower case letters ===
If the original word was capitalized, then the first letter of its abbreviation should retain the capital, for example Lev. for Leviticus. When abbreviating words spelled with lower case letters, there is no need for capitalization, therefore no need for a consistent rule.

=== Periods (full stops) and spaces ===
A period (full stop) is sometimes written after an abbreviated word, but there is much disagreement and many exceptions.

There is never a stop/period between letters of the same word. For example, ''Tiberius'' is abbreviated as ''Tb.'' and not as ''T.b.''.

In formal [[British English]] it is more common to write abbreviations with full stops if the word has been cut at the point of abbreviation but not otherwise: for example, ''Street'' — ''"St[reet]"'' — becomes ''"St."''{{Fact|date=October 2007}}, but ''"Saint"'' — ''"S[ain]t"'' — becomes ''"St"''{{Fact|date=October 2007}}.

In [[American English]], the period is usually added if the abbreviation might otherwise be interpreted as a word, but some American writers do not use a period here. Sometimes, periods are used for certain initialisms but not others; a notable instance in American English is to write ''[[United States]]'', ''[[European Union]]'', and ''[[United Nations]]'' as ''U.S.'', ''EU'', and ''UN'' respectively.

A third standard removes the full stops from all abbreviations (both ''"Saint"'' and ''"Street"'' become ''"St"'') .

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

Spaces are generally not used between single letter abbreviations of words in the same phrase, so one almost never encounters "U. S.".

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

=== Plural Forms ===
To form the plural of an abbreviation, a number, or a capital letter used as a noun, simply add a lowercase ''s'' to the end.

* A group of MPs
* The roaring '20s
* Mind your Ps and Qs

To form the plural of an abbreviation with periods, a lowercase letter used as a noun, and abbreviations or capital letters that would be ambiguous or confusing if the 's' alone were added, use an apostrophe and an ''s''.

* A group of Ph.D.'s
* The x's of the equation
* Sending SOS's

While some authors use the apostrophe in all plural abbreviated forms, it is generally best avoided except as above to prevent ambiguity with the possessive form.[http://pcroot.cern.ch/TaligentDocs/TaligentOnline/DocumentRoot/1.0/Docs/books/SG/SG_1.html]
[http://www.writersblock.ca/tips/monthtip/tipmar96.htm]
[http://www.editfast.com/english/grammar/apostrophes/apostrophe_plurals.htm]

=== Conventions followed by publications and newspapers ===
==== In the United States ====

Publications based in the U.S. tend to follow the style guides of the [[Chicago Manual of Style]] and the [[Associated Press]]. The [[U.S. Government]] follows a style guide published by the [[U.S. Government Printing Office]].

However, there is some inconsistency in abbreviation styles, as they are not rigorously defined by style guides. Some two-word abbreviations, like "United Nations", are abbreviated with uppercase letters and periods, and others, like "personal computer" (PC) and "compact disc" (CD), are not; rather, they are typically abbreviated without periods and in uppercase letters. A third variation is to use lowercase letters with periods; this is used by Time Magazine in abbreviating "public relations" (p.r.). Moreover, even three-word abbreviations (most U.S. publications use uppercase abbreviations without periods) are sometimes not consistently abbreviated, even within the same article.

''[[The New York Times]]'' is unique in having a consistent style by always abbreviating with periods: P.C., I.B.M., P.R. This is in contrast with the trend of British publications to completely make do without periods for convenience.

==== In Britain ====
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 full stops or periods in all abbreviations. These include:
** Social titles, like Ms or Mr (though these would usually not have had full stops — see above) Capt, Prof, ''etc.;''
** Two-letter abbreviations for countries (''"US"'', not ''"U.S."'');
** Abbreviations beyond three letters (full caps for all except initialisms);
** 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 newspaper ''[[The Economist]]'' which writes ''"Mr F. W. de Klerk"''.
** Scientific units (see Measurement below).
* [[Acronym]]s are often referred to with only the first letter of the abbreviation capitalised. For instance, the [[North Atlantic Treaty Organisation]] 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).
* [[Initialism]]s are always written in capitals; for example the ''"British Broadcasting Corporation"'' is abbreviated to ''"BBC"'', never ''"Bbc"''. An initialism is similar to acronym but is not pronounced as a word.
* When abbreviating scientific units, no space is added between the number and unit (100mph, 100m, 10cm, 10°C). (This is contrary to the SI standard, see below.)

==== Miscellaneous and general rules ====
* Plurals are often formed by doubling the last letter of the abbreviation. Most of these deal with writing and publishing: ''MS''=''manuscript'', ''MSS''=''manuscripts''; ''l''=''line'', ''ll''=''lines''; ''p''=''page'', ''pp''=''pages''; ''s''=''section'', ''ss''=''sections''; ''op.''=''opus'', ''opp.''=''opera''. This form, derived from [[Latin]] is used in Europe in many places: dd=[[Point (typography)|didot]]s. ''"The following (lines or pages)"'' is denoted by ''"ff"''. One example that does not concern printing is ''hh''=''[[hand (unit)|hands]]''.
* A doubled letter also 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) [[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.
* It is usually advised to spell out the abbreviation where it is new or unfamiliar to the reader (''UNESCO'' in a magazine about music, because it refers to the [[United Nations Educational, Scientific and Cultural Organization]], whose work does not concern the music).

==Measurement==

The [[International System of Units]] (SI) defines a set of base units, from which other "derived" units may be obtained. The abbreviations, or more accurately "symbols" (using Roman letters, or Greek in the case of [[ohm]]) for these units are also clearly defined together with a set of prefixes, themselves symbolised (abbreviated) with Roman letters (except only for micro, which uses the Greek letter ''µ''), denoting powers of ten. The system is internationally recognised. Periods are not used, except as described below. Unit symbols do not have plural forms.

Units are written either in full, including the base units and their prefixes, or with all symbols. When a unit is written in full, it is written in all lower case. For example, ''megaampere'' for ''MA''.

There should never be a period after or inside a unit; both '10 k.m.' and '10 k.m' are wrong — the only correct form is '10 km' (only followed with a period when at the end of a sentence).

A period "within" a compound unit denotes multiplication of the base units on each side of it. Ideally, this period should be raised to the centre of the line, but often it is not. For instance, '5 ms' means 5 millisecond(s), whereas '5 m.s' means 5 metre·second(s). The "m.s" here is a compound unit formed from the product of two fundamental SI units — metre and second.

There should always be a (non-breaking) space between the number and the unit — '25 km' is correct, and '25km' is incorrect.

The [[letter case|case of letters]] (uppercase or lowercase) has meaning in the SI system, and should never be changed in a misguided attempt to follow an abbreviation style. For example, "10 S" denotes 10 siemens (a unit of conductance), while "10 s" denotes 10 seconds. Any unit named after a person is denoted by a symbol with an upper case first letter (S, Pa, A, V, N, Wb, W), but spelt out in full in lower case, (siemens, pascal, ampere, volt, newton, weber and watt). By contrast g, l, m, s, cd, ha represent gramme, litre, metre, second, candela and hectare respectively. The one slight exception to this rule is that the symbol for litre is allowed to be L to help avoid confusion with an upper case ''i'' or a [[1 (number)|one]] in some [[typeface]]s — compare l, I, and 1.

Likewise, the abbreviations of the prefixes denoting powers of ten are case-sensitive: m (milli) represents a thousandth, but M (mega) represents a million, so by inadvertent changes of case one may introduce (in this example) an error of a factor of 1 000 000 000. When a unit is written in full, the whole unit is written in lowercase, including the prefix: millivolt for mV, nanometre for nm, gigacandela for Gcd.

The above rules, if followed, ensure that the SI system is always unambiguous, so for instance mK denotes millikelvin, MK denotes megakelvin, K.m denotes kelvin.metre, and km denotes kilometre. Forms such as k.m and Km are ill-formed and technically meaningless in the SI system, although the meaning might be inferred from the context.

==History==
After [[World War II]], the British greatly reduced their use of the full stop and other punctuations after abbreviations in at least semi-formal writing, while the Americans more readily kept its use until more recently, and still maintain it more than Britons. The classic example, considered by their American counterparts quite curious, was the maintenance of the internal comma in a British organization of secret agents called the "Special Operations, Executive" — "S.O.,E" — which is not found in histories written after about 1960.

But before that, many Britons were more scrupulous at maintaining the French form. In [[French language|French]], the period only follows an abbreviation if the last letter in the abbreviation is ''not'' the last letter of its antecedent: "M." is the abbreviation for "monsieur" while "Mme" is that for "madame". Like many other cross-[[English Channel|channel]] linguistic acquisitions, many Britons readily took this up and followed this rule themselves, while the Americans took a simpler rule and applied it rigorously.

Over the years, however, the lack of convention in some style guides has made it difficult to determine which two-word abbreviations should be abbreviated with periods and which should not. The U.S. media tend to abbreviate two-word abbreviations like United States (U.S.), but not personal computer (PC) or television (TV), which is{{Fact|date=February 2007}} a source of confusion. Many British publications have gradually done away with the use of periods in abbreviations completely.

Minimisation of punctuation in typewritten matter became economically desirable in the 1960s and 1970s for the many users of carbon-film [[IBM_Selectric_typewriter#Ribbons|ribbons]], since a period or comma consumed the same length of non-reusable expensive ribbon as did a capital letter.

==Examples==
*[[List of classical abbreviations]]
*[[List of medieval abbreviations]]
*[[List of abbreviations in use in 1911]]
*[[List of acronyms and initialisms]]
*[[Wiktionary:Wiktionary:Abbreviations in Webster|The abbreviations used in the 1913 edition of Webster's dictionary]]

== External links ==
* [http://www.abbreviations.com Abbreviations.com] — a human edited database of acronyms and abbreviations
* [http://www.acronymfinder.com Acronym Finder] — a human edited database of acronyms and abbreviations (over 550,000 entries)
* [http://www.auctionslanguage.com AuctionSlanguage.com] — a human edited database of auction related acronyms and abbreviations

[[Category:Abbreviations|*]]

[[bg:Абревиатура]]
[[de:Abkürzung]]
[[es:Abreviatura]]
[[eo:Mallongigo]]
[[fr:Abréviation]]
[[it:Abbreviazione]]
[[mn:Товчлол]]
[[pl:Skrót]]
[[ru:Аббревиатура]]
[[tk:Abbrewiatura]]
[[uk:Абревіатура]]'''