Acronyms and initialisms are abbreviations that are formed using the initial components in a phrase or name. These components may be individual letters (as in CEO) or parts of words (as in Benelux). There is no universal agreement on the precise definition of the various terms (see nomenclature), nor on written usage (see orthographic styling). While popular in recent English, such abbreviations have historical use in English as well as other languages. As a type of word formation process, acronyms and initialisms are viewed as a subtype of blending.
While the word abbreviation refers to any shortened form of a word or a phrase, some have used initialism or alphabetism to refer to an abbreviation formed simply from, and used simply as, a string of initials. In 1943, Bell Laboratories coined the term acronym as the name for a word created from the first letters of each word in a series of words (such as sonar, created from sound navigation and ranging). The terms initialism and alphabetism are neither widely used nor widely known. The term acronym is widely used to describe any abbreviation formed from initial letters.
Most dictionaries define acronym to mean "a word" in its original sense,  while some include a secondary indication of usage, attributing to acronym the same meaning as that of initialism. According to the primary definition found in most dictionaries, examples of acronyms would include NATO (pronounced /ˈneɪtoʊ/), scuba (/ˈskuːbə/), and radar (/ˈreɪdɑr/), while examples of initialisms would include FBI (/ˌɛfˌbiːˈaɪ/) and HTML (/ˌeɪtʃˌtiːˌɛmˈɛl/).
There is also some disagreement as to what to call abbreviations that some speakers pronounce as letters and others pronounce as a word. For example, the terms URL and IRA can be pronounced as individual letters: /ˌjuːˌɑrˈɛl] and /ˌaɪˌɑrˈeɪ/ respectively; or as a single word: /ˈɜrl/ and /ˈaɪrə/ respectively. Such constructions, however—regardless of how they are pronounced—if formed from initials, may be identified as initialisms without controversy.
The term for the word-by-word reconstruction of an acronym or initialism is an expansion.
Acronymy, like retronymy, is a linguistic process that has existed throughout history but for which there was little to no naming, conscious attention, or systematic analysis until relatively recent times. Like retronymy, it became much more common in the 20th century than it had formerly been.
Ancient examples of acronymy (regardless of whether there was metalanguage at the time to describe it) include the following:
During the mid to late 19th century, an initialism-disseminating meme spread through the American and European business communities: abbreviating corporation names in places where space was limited for writing—such as on the sides of railroad cars (e.g., Richmond, Fredericksburg and Potomac Railroad → RF&P); on the sides of barrels and crates; and on ticker tape and in the small-print newspaper stock listings that got their data from it (e.g., American Telephone and Telegraph Company → AT&T). Some well-known commercial examples dating from the 1890s through 1920s include Nabisco (National Biscuit Company), Esso (from S.O., from Standard Oil), and Sunoco (Sun Oil Company).
The widespread, frequent use of acronyms and initialisms across the whole range of registers is a relatively new linguistic phenomenon in most languages, becoming increasingly evident since the mid-20th century. As literacy rates rose, and as advances in science and technology brought with them a constant stream of new (and sometimes more complex) terms and concepts, the practice of abbreviating terms became increasingly convenient. The Oxford English Dictionary (OED) records the first printed use of the word initialism as occurring in 1899, but it did not come into general use until 1965, well after acronym had become common.
Around 1943, the term acronym was coined to recognize abbreviations and contractions of phrases pronounced as words. (It was formed from the Greek words ἄκρος, akros, "topmost, extreme" and ὄνομα, onoma, "name.") For example, the army offense of being absent without official leave was abbreviated to "A.W.O.L." in reports, but when pronounced as a word ('awol'), it became an acronym. While initial letters are commonly used to form an acronym, the original definition was a word made from the initial letters or syllables of other words, for example UNIVAC from UNIVersal Automatic Computer.
In English, acronyms pronounced as words may be a 20th-century phenomenon. Linguist David Wilton in Word Myths: Debunking Linguistic Urban Legends claims that "forming words from acronyms is a distinctly twentieth- (and now twenty-first-) century phenomenon. There is only one known pre-twentieth-century [English] word with an acronymic origin and it was in vogue for only a short time in 1886. The word is colinderies or colinda, an acronym for the Colonial and Indian Exposition held in London in that year."
Acronyms and initialisms are used most often to abbreviate names of organizations and long or frequently referenced terms. The armed forces and government agencies frequently employ initialisms (and occasionally, acronyms); some well-known examples from the United States are among the "alphabet agencies" created by Franklin D. Roosevelt under the New Deal. Business and industry also are prolific coiners of acronyms and initialisms. The rapid advance of science and technology in recent centuries seems to be an underlying force driving the usage, as new inventions and concepts with multiword names create a demand for shorter, more manageable names. One representative example, from the U.S. Navy, is COMCRUDESPAC, which stands for commander, cruisers destroyers Pacific; it's also seen as "ComCruDesPac". "YABA-compatible" (where YABA stands for "yet another bloody acronym") is used to mean that a term's acronym can be pronounced but is not an offensive word (e.g., "When choosing a new name, be sure it is "YABA-compatible").
The use of initialisms has been further popularized with the emergence of Short Message Systems (SMS). In order to fit messages into the 160-Character limit of SMS, initialisms such as "GF" (girl friend), "LOL" (laughing out loud), and "DL" (download) have been popularized into the mainstream. Although prescriptivist disdain for such neologism is fashionable, and can be useful when the goal is protecting message receivers from crypticness, it is scientifically groundless when couched as preserving the "purity" or "legitimacy" of language; this neologism is merely the latest instance of a perennial linguistic principle—the same one that in the 19th century prompted the aforementioned abbreviation of corporation names in places where space for writing was limited (e.g., ticker tape, newspaper column inches).
Acronyms and initialisms often occur in jargon. An initialism may have different meanings in different areas of industry, writing, and scholarship. The general reason for this is convenience and succinctness for specialists, although it has led some to obfuscate the meaning either intentionally, to deter those without such domain-specific knowledge, or unintentionally, by creating an initialism that already existed.
The medical literature has been struggling to control the proliferation of acronyms as their use has evolved from aiding communication to hindering it. This has become such a problem that it is even evaluated at the level of medical academies such as the American Academy of Dermatology. 
It is not uncommon for acronyms to be cited in a kind of false etymology, called a folk etymology, for a word. Such etymologies persist in popular culture but have no factual basis in historical linguistics, and are examples of language-related urban legends. For example, cop is commonly cited as being supposedly derived from "constable on patrol," posh from "port out, starboard home", and golf from "gentlemen only, ladies forbidden". Taboo words in particular commonly have such false etymologies: shit from "ship/store high in transit" or "special high-intensity training" and fuck from "for unlawful carnal knowledge", or "fornication under carnal knowledge".
Traditionally, in English, abbreviations have been written with a full stop/period/point in place of the deleted part to show the ellipsis of letters, although the colon and apostrophe have also had this role. In the case of most acronyms and initialisms, each letter is an abbreviation of a separate word and, in theory, should get its own termination mark. Such punctuation is diminishing with the belief that the presence of all-capital letters is sufficient to indicate that the word is an abbreviation.
Some influential style guides, such as that of the BBC, no longer require punctuation to show ellipsis; some even proscribe it. Larry Trask, American author of The Penguin Guide to Punctuation, states categorically that, in British English, "this tiresome and unnecessary practice is now obsolete", though some other sources are not so absolute in their pronouncements.
Nevertheless, some influential style guides, many of them American, still require periods in certain instances. For example, The New York Times’ guide recommends following each segment with a period when the letters are pronounced individually, as in K.G.B., but not when pronounced as a word, as in NATO. The logic of this style is that the pronunciation is reflected graphically by the punctuation scheme.
When a multiple-letter abbreviation is formed from a single word, periods are generally not used, although they may be common in informal usage. TV, for example, may stand for a single word (television or transvestite, for instance), and is generally spelled without punctuation (except in the plural). Although PS stands for the single word postscript (or the Latin postscriptum), it is often spelled with periods (P.S.).
The slash ('/', a.k.a. virgule) is sometimes used to show the ellipsis of letters, for instance in the initialisms N/A (not applicable, not available) and w/o (without).
Inconveniently long words used frequently in related contexts can be represented according to their letter count. i18n, for example, abbreviates internationalization, a computer-science term for adapting software for worldwide use. The 18 represents the 18 letters that come between the first and the last in internationalization. Localization can be abbreviated l10n, multilingualization m17n, and accessibility a11y. In addition to the use of a specific number replacing that amount of letters, the more general "x" can be used to replace an unspecified number of letters (e.g. Crxn for crystallization).
The traditional style of pluralizing single letters with the addition of ’s (for example, B’s come after A’s) was extended to some of the earliest initialisms, which tended to be written with periods to indicate the omission of letters; some writers still pluralize initialisms in this way. Some style guides continue to require such apostrophes—perhaps partly to make it clear that the lower case s is only for pluralization and would not appear in the singular form of the word, for some acronyms and abbreviations do include lowercase letters.
However, it has become common among many writers to inflect initialisms as ordinary words, using simple s, without an apostrophe, for the plural. In this case, compact discs becomes CDs. The logic here is that the apostrophe should be restricted to possessives: for example, the CD’s label (the label of the compact disc).
Multiple options arise when initialisms are spelled with periods and are pluralized: for example, whether compact discs may become C.D.’s, C.D.s, CD’s, or CDs. Possessive plurals that also include apostrophes for mere pluralization and periods appear especially complex: for example, the C.D.’s’ labels (the labels of the compact discs). This as yet another reason to use apostrophes only for possessives and not for plurals. In some instances, however, an apostrophe may increase clarity: for example, if the final letter of an abbreviation is S, as in SOS’s, or when pluralizing an abbreviation that has periods. (In The New York Times, the plural possessive of G.I., which the newspaper prints with periods in reference to United States Army soldiers, is G.I.’s, with no apostrophe after the s.)
A particularly rich source of options arises when the plural of an initialism would normally be indicated in a word other than the final word if spelled out in full. A classic example is Member of Parliament, which in plural is Members of Parliament. It is possible then to abbreviate this as M’s P. (or similar), as famously by a former Australian Prime Minister. This usage is less common than forms with s at the end, such as MPs, and may appear dated or pedantic.
The argument that initialisms should have no different plural form (for example, "If D can stand for disc, it can also stand for discs") is generally disregarded because of the practicality in distinguishing singulars and plurals. This is not the case, however, when the abbreviation is understood to describe a plural noun already: for example, U.S. is short for United States, but not United State. In this case, the options for making a possessive form of an abbreviation that is already in its plural form without a final s may seem awkward: for example, U.S.’, U.S.’s, etc. In such instances, possessive abbreviations are often foregone in favor of simple attributive usage (for example, the U.S. economy) or expanding the abbreviation to its full form and then making the possessive (for example, the United States’ economy). On the other hand, in speech, the pronunciation United States’s sometimes is used.
Abbreviations that come from single, rather than multiple, words—such as TV (television)—are pluralized without apostrophes: the apostrophe should be reserved for the possessive (TVs).
In some languages, the convention of doubling the letters in the initialism is used to indicate plural words: for example, the Spanish EE.UU., for Estados Unidos (United States). This old convention is still followed for a limited number of English abbreviations, such as SS. for Saints, pp. for pages (although this is actually derived from the Latin abbreviation for paginae) or MSS for manuscripts.
Acronyms that are now always rendered in the lower case are pluralized as regular English nouns: for example, lasers.
When an initialism is part of a function in computing that is conventionally written in lower case, it is common to use an apostrophe to pluralize or otherwise conjugate the token. This practice results in such sentences like "Be sure to remove extraneous .dll’s" (more than one .dll). However despite the pervasiveness of this practice, it is generally held to be technically incorrect; the preferred method being to simply append an s, without the apostrophe.
In computer lingo, it is common to use the name of a computer program, format, or function, acronym or not, as a verb. In such verbification of abbreviations, there is confusion about how to conjugate: for example, if the verb IM (pronounced as separate letters) means to send (someone) an instant message, the past tense may be rendered IM’ed, IMed, IM’d, or IMd—and the third-person singular present indicative may be IM’s or IMs.
The most common capitalization scheme seen with acronyms and initialisms is all-uppercase (all-caps), except for those few that have linguistically taken on an identity as regular words, with the acronymous etymology of the words fading into the background of common knowledge, such as has occurred with the words scuba, laser, and radar — these are known as anacronyms (a portmanteau with anachronism).
Small caps are sometimes used in order to make the run of capital letters seem less jarring to the reader. For example, the style of some American publications, including the Atlantic Monthly and USA Today, is to use small caps for acronyms and initialisms longer than three letters; thus "U.S." and "FDR" in normal caps, but "NATO" in small caps. The initialisms "AD" and "BC" are often smallcapped as well, as in: "From 4004 BC to AD 525."
On the copyediting end of the publishing industry, where the aforementioned distinction between acronyms (pronounced as a word) and initialisms (pronounced as a series of letters) is usually maintained, some publishers choose to use cap/lowercase (c/lc) styling for acronyms, reserving all-caps styling for initialisms. Thus Nato and Aids (c/lc), but USA and FBI (caps). For example, this is the style used in The Guardian, and BBC News typically edits to this style. The logic of this style is that the pronunciation is reflected graphically by the capitalization scheme.
Some style manuals also base the letters' case on their number. The New York Times, for example, keeps NATO in all capitals (while several guides in the British press may render it Nato), but uses lower case in Unicef (from "United Nations International Children’s Emergency Fund") because it is more than four letters, and to style it in caps might look ungainly (flirting with the appearance of "shouting capitals").
While typically abbreviations exclude the initials of short function words (such as "and", "or", "of", or "to"), they are sometimes included in acronyms to make them pronounceable. Sometimes the letters representing these words are written in lower case, such as in the cases of TfL (Transport for London) and LotR (Lord of the Rings). This usually occurs when the acronym represents a multi-word proper noun.
Numbers (both cardinal and ordinal) in names are often represented by digits rather than initial letters: as in 4GL (Fourth generation language) or G77 (Group of 77). Large numbers may use metric prefixes, as with Y2K for "Year 2000" (sometimes written Y2k, because the SI symbol for 1000 is k - not K, which stands for kelvin). Exceptions using initials for numbers include TLA (three-letter acronym/abbreviation) and GoF (Gang of Four). Abbreviations using numbers for other purposes include repetitions, such as W3C ("World Wide Web Consortium"); pronunciation, such as B2B ("business to business"); and numeronyms, such as i18n ("internationalization"; 18 represents the 18 letters between the initial i and the final n).
In some cases, an acronym or initialism has been redefined as a nonacronymous name, creating a pseudo-acronym. For example, the letters making up the name of the SAT (pronounced as letters) college entrance test no longer officially stand for anything. This trend has been common with many companies hoping to retain their brand recognition while simultaneously moving away from what they saw as an outdated image: American Telephone and Telegraph became AT&T (its parent/child, SBC, followed suit prior to its acquisition of AT&T and after its acquisition of a number of the other Baby Bells, changing from Southwestern Bell Corporation), Kentucky Fried Chicken became KFC to deemphasize the role of frying in the preparation of its signature dishes , British Petroleum became BP to emphasize that it was no longer only an oil company (captured by its motto "beyond petroleum"), Silicon Graphics, Incorporated became SGI to emphasize that it was no longer only a computer graphics company. DVD now has no official meaning: its advocates could not agree on whether the initials stood for "Digital Video Disc" or "Digital Versatile Disc," and now both terms are used.
Pseudo-acronyms may have advantages in international markets: for example, some national affiliates of International Business Machines are legally incorporated as "IBM" (or, for example, "IBM Canada") to avoid translating the full name into local languages. Similarly, "UBS" is the name of the merged Union Bank of Switzerland and Swiss Bank Corporation.
Rebranding can lead to redundant-acronym syndrome syndrome, as when Trustee Savings Bank became TSB Bank, or when Railway Express Agency became REA Express. A few high-tech companies have taken the redundant acronym to the extreme: for example, ISM Information Systems Management Corp. and SHL Systemhouse Ltd. An example in entertainment is the television show CSI: Crime Scene Investigation, where the redundancy was likely designed to educate new viewers as to what "CSI" stood for.
Another common example is RAM memory, which is redundant because RAM (random-access memory) includes the initial of the word memory. PIN stands for personal identification number, obviating the second word in PIN number. Other examples include ATM machine (automatic teller machine machine), EAB bank (European American Bank bank), DC comics (detective comics comics), HIV virus (human immunodeficiency virus virus), Microsoft's NT Technology (New Technology Technology) and the formerly redundant SAT test (Scholastic Achievement/Aptitude/Assessment Test test, now simply SAT Reasoning Test).
Sometimes, the initials continue to stand for an expanded meaning, but the original meaning is simply replaced. Some examples:
A backronym (or bacronym) is a phrase that is constructed "after the fact" from a previously existing word. For example, the novelist and critic Anthony Burgess once proposed that the word "book" ought to stand for "Box Of Organised Knowledge." A classic real-world example of this in action was the name of the predecessor to the Apple Macintosh, The Apple Lisa, which was said to refer to "Local Integrated Software Architecture", but Steve Jobs' daughter, born 1978, was named Lisa. Wags also came up with "Lisa: Invented Stupid Acronym" and "Let's Invent Some Acronym" to poke fun at the activity.
A contrived acronym is one that has been deliberately designed in such a way that it will be especially apt as a name for the thing being named (such as by having a dual meaning or by borrowing the positive connotations of an existing word). Some examples of contrived acronyms are USA PATRIOT, CAN SPAM,CAPTCHA, and ACT UP. The clothing company French Connection began referring to itself as fcuk, standing for "French Connection United Kingdom." The company then created t-shirts and several advertising campaigns that exploit the acronym's similarity to the taboo word "fuck". See the list of fictional espionage organizations for more examples of contrived acronyms.
Some acronyms are chosen deliberately to avoid a name considered undesirable: for example, Verliebt in Berlin (ViB), a German telenovela, was first intended to be Alles nur aus Liebe (All for Love), but was changed to avoid the resultant acronym ANAL. Similarly, the Computer Literacy and Internet Technology qualification is known as CLaIT, rather than CLIT. In Canada, the Canadian Conservative Reform Alliance (Party) was quickly renamed to the Canadian Reform Conservative Alliance when its opponents pointed out that its initials spelled CCRAP (see crap). (The satirical magazine Frank had proposed alternatives to CCRAP, namely SSHIT and NSDAP.) Two Irish Institutes of Technology (Galway and Tralee) had to choose different acronyms to other institutes when they were upgraded from Regional Technical colleges. Tralee RTC became the Institute of Technology Tralee (ITT), as opposed to Tralee Institute of Technology (TIT). Galway RTC became Galway-Mayo Institute of Technology (GMIT), as opposed to Galway Institute of Technology (GIT). Team in Training is known as TNT and not TIT. Technological Institute of Textile & Sciences is still known as TITS.
Contrived acronyms differ from backronyms in that they were originally conceived with the artificial expanded meaning, while backronyms are later invented expansions.
A macronym is an acronym in which one or more letters stand for acronyms themselves. A special case of a macronym is the recursive acronym, which directly or indirectly refers to itself when expanded. One of the earliest examples of such appears in The Hacker's Dictionary as MUNG, which stands for "MUNG Until No Good"
Six examples of macronyms are:
In English language discussion of languages with syllabic or logographic writing systems (such as Chinese, Japanese, and Korean), acronym describes short forms that often take the first character of each multi-character element.
For example, the name of Beijing University in Standard Mandarin consists of four syllables: Bei-jing Da-xue (北京大学), where Da-xue means "university". This is commonly abbreviated to just Bei-Da (北大). In some cases a character in each element is used to form the short form, but not necessarily the first one. For example, Hong Kong University—Xiang-gang Da-xue (香港大学) is known as Gang-da (港大) instead of Xiang-da (香大). In addition, longer phrases may be abbreviated more drastically. An example is the National People's Congress, Quan-guo Ren-min Dai-biao Da-hui (全国人民代表大会), which is shortened to Ren-Da (人大). In describing such languages, the term initialism is inapplicable.
There is also a widespread use of acronyms and initialisms in Indonesia in every aspect of social life. For example, the Golkar political party stands for Partai Golongan Karya, Monas stands for "Monumen Nasional" (National Monument), the Angkot public transport stands for "Angkutan Kota", warnet stands for "warung internet" or internet cafe, and many others.
Mid-20th century German showed a tendency toward acronym-contractions of the Gestapo (for Geheime Staatspolizei) type: other examples are Hiwi (for Hilfswilliger, non-German volunteer in the German Army); Vokuhila (for "vorne kurz, hinten lang," "short in the front, long in the back," i.e. a mullet; Vopo (for Volkspolizist, member of police force in the GDR); Mufuti or MuFuTi (Multifunktionstisch - multi functional table in the GDR). Mockingly, the people call this tendency AbKüFi (Abkürzfimmel – strange habit of abbreviating).
It is common to take more than just one initial letter from each of the words composing the acronym; regardless of this, the abbreviation sign is always written next to the last letter, even if by this it separates letters of the same original word. Examples: ארה"ב (for ארצות הברית, the United States); ברה"מ (for ברית המועצות, the Soviet Union); ראשל"צ (for ראשון לציון, Rishon LeZion); ביה"ס (for בית הספר, the school). An example that takes only the initial letters from its component words is צה"ל ("Tzahal", for צבא הגנה לישראל, Israel Defense Forces).
In Swahili, acronyms are common for naming organizations such as TUKI which stands for "Taasisi ya Uchunguzi wa Kiswahili" (the institute for Swahili research). Multiple initial letters (often the initial syllable of words) are often drawn together.
In languages where nouns are declined, various methods are used. An example is Finnish, where a colon is used to separate inflection from the letters:
The process above is similar to how, in English, hyphens are used for clarity when prefixes are added to acronyms. Thus prewar policy (hyphen unneeded) but pre-NATO policy (rather than preNATO).
In languages such as Scottish Gaelic and Irish, where lenition (initial consonant mutation) is commonplace, acronyms must also be modified in situations where case and context dictate it. In the case of Scottish Gaelic, a lower case "h" is added after the initial consonant; for example, BBC Scotland in the genitive case would be written as BhBC Alba, with the acronym pronounced "VBC". Similarly, the Gaelic acronym for "television" (gd: telebhisean) is TBh, pronounced "TV", as in English.
acronyms A number of commentators (as Copperud 1970, Janis 1984, Howard 1984) believe that acronyms can be differentiated from other abbreviations in being pronounceable as words. Dictionaries, however, do not make this distinction because writers in general do not:Pyles & Algeo 1970 divide acronyms into "initialisms," which consists of initial letters pronounced with the letter names, and "word acronyms," which are pronounced as words. Initialism, an older word than acronym, seems to be too little known to the general public to serve as the customary term standing in contrast with acronym in a narrow sense.
"The powder metallurgy industry has officially adopted the acronym 'P/M Parts'" —Precision Metal Molding, January 1966.
"Users of the term acronym make no distinction between those which are pronounced as words … and those which are pronounced as a series of characters" —Jean Praninskas, Trade Name Creation, 1968.
"It is not J.C.B.'s fault that its name, let alone its acronym, is not a household word among European scholars" —Times Literary Supp. 5 February 1970.
"… the confusion in the Pentagon about abbreviations and acronyms—words formed from the first letters of other words" —Bernard Weinraub., N.Y. Times, 11 December 1978
Strictly, an acronym is a string of initial letters pronounceable as a word, such as "NATO". Although WDEU [devoted exclusively to disputed usage] says, "Dictionaries, however, do not make this distinction [between acronyms and initialisms] because writers in general do not"; but two of the best known books on acronyms are titled Acronyms, Initialisms and Abbreviations Dictionary (19th ed., Gale, 1993) and Concise Dictionary of Acronyms and Initialisms (Facts on File, 1988).
initialism (plural initialisms)