An abbreviation (from Latin brevis, meaning 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., abbrv. or abbrev.
In strict analysis, abbreviations should not be confused with contractions or acronyms (including initialisms), with which they share some semantic and phonetic functions, though all three are connoted by the term "abbreviation" in loose parlance. An abbreviation is a shortening by any method; a contraction is a reduction of size by the drawing together of the parts. A contraction of a word is made by omitting certain letters or syllables and bringing together the first and last letters or elements; an abbreviation may be made either by omitting certain portions from the interior or by cutting off a part. A contraction is an abbreviation, but an abbreviation is not necessarily a contraction. However, normally acronyms are regarded as a subgroup of abbreviations (e.g. by the Council of Science Editors).
Abbreviations can also be used to give a different context to the word itself, such as "PIN Number" (wherein if the abbreviation were removed the context would be invalid).
See also: Scribal abbreviation. Abbreviations have been used as long as phonetic scripts have existed, in some sense actually being more common in early literacy, where spelling out a whole word was often avoided, initial letters commonly being used to represent words in specific application. By classical Greece and Rome, the reduction of words to single letters was still normal, but can default.
An increase in literacy has, historically, sometimes spawned a trend toward abbreviation. The standardisation of English in the 15th through 17th centuries included such a growth in the use of abbreviations. At first, abbreviations were sometimes represented with various suspension signs, not only periods. For example, sequences like ‹er› were replaced with, as in for master and for exacerbate. While this may seem trivial, it was symptomatic of an attempt by people manually reproducing academic texts to reduce the copy time. An example from the Oxford University Register, 1503:
During the growth of philological linguistic theory in academic Britain, abbreviating became very fashionable. The use of abbreviation for the names of "Father of modern etymology" J. R. R. Tolkien and his friend C. S. Lewis, and other members of the Oxford literary group known as the Inklings, are sometimes cited as symptomatic of this. Likewise, a century earlier in Boston, a fad of abbreviation started that swept the United States, with the globally popular term OK generally credited as a remnant of its influence. 
After World War II, the British greatly reduced the use of the full stop and other punctuation points after abbreviations in at least semi-formal writing, while the Americans more readily kept such 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 organisation 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, 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-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 use periods in two-word abbreviations like United States (U.S.), but not personal computer (PC) or television (TV). Many British publications have gradually done away with the use of periods in abbreviations.
Minimization of punctuation in typewritten material became economically desirable in the 1960s and 1970s for the many users of carbon-film ribbons, since a period or comma consumed the same length of non-reusable expensive ribbon as did a capital letter.
Widespread use of electronic communication through mobile phones and the Internet during the 1990s allowed for a marked rise in colloquial abbreviation. This was due largely to increasing popularity of textual communication services such as instant- and text messaging. SMS, for instance, supports message lengths of 160 characters at most (using the GSM 03.38 character set). This brevity gave rise to an informal abbreviation scheme sometimes called Textese, with which 10% or more of the words in a typical SMS message are abbreviated. More recently Twitter, a popular social network service, began driving abbreviation use with 140 character message limits.
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.
If the original word was capitalised, then the first letter of its abbreviation should retain the capital, for example Lev. for Leviticus. When abbreviating words that are originally spelled with lower case letters, there is no need for capitalisation.
A period (full stop) is sometimes written after an abbreviated word, but there are exceptions and a general lack of consensus about when this should happen.
In British English, according to Hart's Rules, the general rule is that abbreviations (in the narrow sense that includes only words with the ending, and not the middle, dropped) terminate with a full stop (period), whereas contractions (in the sense of words missing a middle part) do not.
|The Reverend||Contraction (or Abbreviation)||Revd (or Rev.)||Rev–d|
|The Right Honourable||Contraction and Abbreviation||Rt Hon.||R–t Hon...|
In American English, the period is usually included. 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.
A third standard removes the full stops from all abbreviations. 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.)
Acronyms that were originally capitalised (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, and 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, only one period is used: The capital of the United States is Washington, D.C.
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.
To indicate the plural of the abbreviation of a unit of measure, the same form is used as in the singular.
When an abbreviation contains more than one full point, Hart's Rules recommends to put the s after the final one.
However, subject to any house style or consistency requirement, the same plurals may be rendered less formally as:
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.
However, the apostrophe can be dispensed with if the items are set in italics or quotes:
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.
|Singular abbreviation||Singular Word||Plural abbreviation||Plural Word||Discipline|
|f.||following line or page||ff.||following lines or pages||notes|
|s. (or §)||section||ss. (or §§)||sections||notes|
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. The National Institute of Standards and Technology sets the style for abbreviations of units.
Many British publications follow some of these guidelines in abbreviation:
The shorthand "in" applies to English only – in Afrikaans for example, the shorthand "dm" is used for the equivalent Afrikaans word "duim". Since both "in" and "dm" are contractions of the same word, but in different languages, they are abbreviations. A symbol on the other hand, defined as "Mark or character taken as the conventional sign of some object or idea or process" applies the appropriate shorthand by substitution rather than by contraction. Since the shorthand for kilometre (Quilômetro in Portuguese or Χιλιόμετρο in Greek) is "km" in both languages and the letter "k" does not appear in the expansion of either translation, "km" is a symbol as it is a substitution rather than a contraction.
In the International System of Units (SI) manual the word "symbol" is used consistently to define the shorthand used to represent the various SI units of measure. The manual also defines the way in which units should be written, the principal rules being:
A syllabic abbreviation is an abbreviation formed from (usually) initial syllables of several words, such as Interpol = International + police. It is basically a variant of the acronym.
Syllabic abbreviations should be distinguished from portmanteaus, which combine two words without necessarily taking whole syllables from each.
Syllabic abbreviations are not widely used in English or French. The United States Navy, however, often uses syllabic abbreviations, as described below.
On the other hand, they prevailed in Germany under the Nazis and in the Soviet Union for naming the plethora of new bureaucratic organisations. For example, Gestapo stands for Geheime Staats-Polizei, or "secret state police". Similarly, Comintern stands for the Communist International. This has caused syllabic abbreviations to have negative connotations (as in Orwell's Newspeak), notwithstanding that such abbreviations were used in Germany even before the Nazis came to power, e.g., Schupo for Schutzpolizei.
Syllabic abbreviations were also typical for the German language used in the German Democratic Republic, e.g. Stasi for Staatssicherheit ("state security", the secret police) or Vopo for Volkspolizist ("people's policeman").
East Asian languages whose writing uses Chinese-originated ideograms instead of an alphabet form abbreviations similarly by using key characters from a term or phrase. For example, in Japanese the term for the United Nations, kokusai rengō (国際連合) is often abbreviated to kokuren (国連). (Such abbreviations are called ryakugo (略語) in Japanese). The syllabic abbreviation is frequently used for universities: for instance, Běidà (北大) for Běijīng Dàxué (北京大学, Peking University) and Tōdai (東大) for Tōkyō daigaku (東京大学, University of Tokyo). The English phrase "Gung ho" originated as a Chinese abbreviation.
See also: Neologism.
Partially-syllabic abbreviations are preferred by the US Navy, as it increases readability amidst the large number of initialisms 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", while COMNAVAIRLANT would be "Commander, Naval Air Force (in the) Atlantic."