Wikipedia:Manual of Style/Abbreviations
|This guideline is a part of the English Wikipedia's Manual of Style. Use common sense in applying it; it will have occasional exceptions. Please ensure that any edits to this page reflect consensus.|
|Manual of Style|
This guideline covers the use of abbreviations, including acronyms, contractions and shortenings, in the English Wikipedia. Maintaining a consistent abbreviation style will allow Wikipedia to be read, written, edited, navigated and used more easily by readers and editors alike. The style should always be consistent within a page. If a guideline conflicts with the correct usage of a proper name, ignore it. The abbreviation style used in quotations from written sources should always be written exactly as in the original source, unless it is a Wikipedia-made translation.
Always consider whether it is better to simply write a word or phrase out in full, thus avoiding potential confusion for those not familiar with its abbreviation. Remember that Wikipedia does not have the same space constraints as paper.
Full stops 
Modern style is to use a full stop (period) after a shortening (although there are many exceptions) but no full stops with an acronym. In the case of an acronym containing full stops between letters, it should also have a full stop after the final letter. If an abbreviation ending in a full stop ends a sentence, do not use an extra full stop (e.g. New York is in the U.S. and not New York is in the U.S..).
Contractions that contain an apostrophe (don't, shouldn't, she'd) never take a period (except at the end of a sentence, of course). They are also not used except in quotations or titles of works, as noted below. Contractions that do not contain an apostrophe almost always take a period in North American English, but the stop is optional in British English: Doctor can be abbreviated Dr. in American and Canadian English, but Dr. or Dr in British English. If in doubt, or if the dot-less usage could be confusing in the context, use the stop. An exception is units of measurement, which never use periods. (see WP:Manual of Style/Dates and numbers).
Acronyms are abbreviations formed, usually, from the initial letters of words in a phrase.
- Capitalisation: Some acronyms are written with all capital letters, some with a mixture of capitals and lower-case letters and some are written as common nouns (e.g. laser). Acronyms whose letters are pronounced individually (which is what some call "initialisms", for example FBI, EU) are written in capitals.
- Spacing: The letters of acronyms should not be spaced.
- Plurals: Plural acronyms are written with a lower-case s after the abbreviation, without an apostrophe, unless full stops are used between the letters (e.g. ABCs or A.B.C.'s). Note that Wikipedia generally avoids using full stops in upper-case acronyms.
Unless specified in the "Exceptions" section below, an acronym should be written out in full the first time it is used on a page, followed by the abbreviation in parentheses, e.g. Millennium Development Goals (MDGs). Common exceptions to this rule are post-nominal initials because writing them out in full would cause clutter. To save space, in "small spaces" (infoboxes, navboxes and tables), acronyms do not need to be written out in full. When not written out in full on the first use on a page, an acronym should be linked. An unambiguous acronym can be linked as is, but an ambiguous acronym should be linked to its expansion.
Ship names 
Time zones 
Acronyms in this table do not need to be written out in full upon first use, except in their own articles or where not doing so would cause ambiguity.
|AD||anno Domini ('in the year of our Lord')||Should not be written out in full in dates and does not need to be linked. Do not use in the year of our lord or any other translation of Anno Domini.|
|AIDS||acquired immunodeficiency syndrome|
|a.k.a. or AKA||also known as||Should only be used in small spaces, otherwise use the full phrase. It does not need to be linked. Never use aka.|
|AM||amplitude modulation||Does not need to be written out in full on first use.|
|am||ante meridiem||Should not be written out in full in times, and does not need to be linked. It should not be written AM or A.M.|
|ANZAC||Australian and New Zealand Army Corps|
|BBC||British Broadcasting Corporation||Does not need to be written out in full on first use.|
|BC||before Christ||Should not be written out in full in dates and does not need to be linked.|
|BCE||Before Common Era||Should not be written out in full in dates.|
|CD||Compact Disc||Does not need to be written out in full on first use.|
|CE||Common Era||Should not be written out in full in dates.|
|DVD||Digital Versatile Disc||Should not be written out in full and should not be linked to its expansion.|
|e.g.||exempli gratia ('for example')||Should not be written out in full, italicised or linked in normal usage.[under discussion]|
|EU||European Union||Does not need to be written out in full on first use, nor provided on first use in round brackets after the full name if written out.|
|FM||frequency modulation||Does not need to be written out in full on first use.|
|HIV||human immunodeficiency virus||Does not need to be written out in full on first use.|
|i.e.||id est ('that is' / 'in other words')||Should not be written out in full, italicised or linked in normal usage.[under discussion]|
|laser||light amplification by stimulated emission of radiation|
|n/a or N/A||not applicable||Should not be written n.a., N.A., NA or na.|
|NASA||National Aeronautics and Space Administration|
|NATO||North Atlantic Treaty Organization|
|quango||quasi-autonomous non-governmental organization|
|PC||personal computer||Does not need to be written out in full on first use, nor provided on first use in round brackets after the full term if written out.|
|pm||post meridiem||Should not be written out in full in times and does not need to be linked. It should not be written PM or P.M..|
|PRC||People's Republic of China||Does not need to be written out in full on first use, nor provided on first use in round brackets after the full name if written out.|
|radar||radio detection and ranging|
|scuba||self-contained underwater breathing apparatus|
|sonar||sound navigation and ranging|
|TV||television||Should not be written out in full, given in round brackets after the full word, or linked in normal usage.|
|UAE||United Arab Emirates||Does not need to be written out in full on first use, nor provided on first use in round brackets after the full name if written out.|
|UNESCO||United Nations Educational, Scientific and Cultural Organization|
|UNICEF||United Nations Children's Fund|
|US or U.S.||United States||Does not need to be written out in full on first use, nor provided on first use in round brackets after the full name if written out. In articles with "UK", "UAE", etc., use "US". Some American editors prefer to use U.S. otherwise. USA and U. S. of A. should not be used.|
|USB||Universal Serial Bus||Does not need to be written out in full on first use.|
|USSR||Union of Soviet Socialist Republics|
Acronyms in page titles 
Acronyms should be used in a page name if the subject is known primarily by its abbreviation and that abbreviation is primarily associated with the subject (e.g. NATO, UNICEF, NASA). In order to determine the prominence of the abbreviation over the full name, consider checking how the subject is referred to in popular media such as newspapers, magazines, and other publications.
Many acronyms are used for several things; naming a page with the full name helps to avoid clashes. A useful test to determine what an abbreviation usually refers to can be done by checking abbreviations.com and finding the relative usage. If it is found that an acronym is chiefly used to refer to a particular subject, the article on that subject can be expressed as the acronym and a disambiguation page can be used for the other subjects.
Whether the acronym or the spelled-out phrase is preferable in many particular cases is debatable. For instance, "DMCA" and "Digital Millennium Copyright Act" have oscillated as to which is primary and which page redirects. Other less controversial pairs are "MPAA" versus "Motion Picture Association of America" and "IMDb" versus "Internet Movie Database".
In many cases, no decision is necessary because a given acronym has several expansions, none of which is the most prominent. Under such circumstances, an article should be named with the spelled-out phrase and the acronym should be a disambiguation page providing descriptive links to all of them. See, for example, "AJAR", which disambiguates between "African Journal of AIDS Research" and "Australian Journal of Agricultural Research". If the acronym and the full name are both in common use, both pages should exist, with one redirecting to the other (or as a disambiguation page).
Acronyms as disambiguators 
To save space, acronyms should be used as disambiguators, when necessary. For example, "Great Northern Railway (U.S.)" and "Labour Party (UK)". The abbreviations are preferred over United States and United Kingdom, for brevity.
Acronyms in category names 
A contraction is an abbreviation of one or more words that has some or all of the middle letters removed but retains the first and final letters (e.g. Mr and aren't). Missing letters are replaced by an apostrophe in multiple-word contractions. Multiple-word contractions should not be used but single-word contractions are acceptable as long as they are not ambiguous. Uncommon contractions should be linked on the first use on a page.
Prefix titles such as Mr and Dr should not be used. Prefixes of royalty and nobility should be used, however (in accordance with a relevant style guide), but should not be abbreviated. (See Wikipedia:Naming conventions (people)#Titles and styles and Wikipedia:Naming conventions (royalty and nobility).)
Only use initials in a personal name if the name is commonly written that way. An initial should be followed by a full stop and a non-breaking space (
A shortening is an abbreviation of a word for which at least the last letter has been removed (e.g. etc. and rhino). Some shortenings also contain letters that are not present in their expansion (e.g. bike). Whether or not to follow a shortening with a full stop often comes down to individual cases but, as a general rule, use a full stop after a shortening that only exists in writing (e.g. etc.) but not for a shortening that is used in speech (e.g. rhino). Common sense should be applied to judge whether a shortening is acceptable in prose or not – words such as rhino are fine and etc. should be used over et cetera but informal terms, such as wanna, are not used in Wikipedia articles. Uncommon shortenings should be linked on the first use on a page.
Song-writing credits 
Miscellaneous shortenings 
|approx.||approximately||It should only be used in small spaces. It does not need to be linked.|
|c.||circa ('around')||To indicate around, approximately, or about, the unitalicised abbreviation c. is preferred over circa, ca, ca., approximately, or approx. It should not be italicised in normal usage.|
|cf.||confer ("compare" / "consult")||It should be linked on first use.|
|Co.||Company||It should only be used in the names of companies, and (like "PLC", "LLC", "Inc.", "Ltd.", "GMBh") etc., can usually be omitted unless an ambiguity would result. It does not need to be linked.|
|ed. (eds.)||edition/editor (editions/editors)||This shortening (and its plural contraction) should only be used in references. It does not need to be linked.|
|et al.||et alii ("and others")||It should only be used in references.|
|fl.||floruit ("flourished")||It should be linked on first use. Do not use flor. or flr.|
|rev.||revised||It should only be used in references. It does not need to be linked.|
|vs./v.||versus (against / in contrast to)||They do not need to be linked. Prefer "vs." except in legal contexts, where the usage is "v." Not italicized, since it has long been assimilated into the language as an English word.|
|viz.||videlicet ("that is to say" / "namely")||It should be linked on first use.|
Unit symbols 
Miscellaneous symbols 
- Ampersands (&) should only be used in small spaces such as tables and infoboxes, but, preferably, should be avoided even there.
- The at sign (@) should not be used in the place of at in normal text.
Latin abbreviations 
In normal usage, abbreviations of Latin words and phrases should be italicised, except AD, c., e.g., etc. and i.e., which have become ordinary parts of the English language. The expansions of Latin abbreviations should still be italicised, as with most foreign words and phrases (Anno Domini, circa, exempli gratia, et cetera, id est). These are not normally used in article prose.
Do not use &c. in the place of etc.
Abbreviations widely used in Wikipedia 
Wikipedia has found it both practical and efficient to use the following abbreviations, although some can often be replaced by unabbreviated equivalents (that is for i.e., namely for viz., and so on). Versions of non-acronym abbreviations that do not end in stops (periods) are more common in British than North American English, and are always abbreviations that compress a word while retaining its first and last letters, rather than truncating. That said, US military ranks are often given without this punctuation. The Manual of Style on abbreviations, above, eschews the use of periods with acronyms (M.D., Ph.D.).
|Boulevard||Blvd. or Blvd|
|East||E. or E (use only in street addresses, not in other text)|
|Freeway||Fwy. or Fwy|
|Highway||Hwy. or Hwy|
|Motorway||Mwy (the term is not generally used in North America)|
|Mountain||Mtn. or Mtn|
|Mount||Mt. or Mt|
|North||N. or N (use only in street addresses, not in other text)|
|North East or Northeast||N.E. or NE (use only in street addresses, not in other text)|
|North West or Northwest||N.W. or NW (use only in street addresses, not in other text)|
|Road||Rd. or Rd|
|South||S. or S (use only in street addresses, not in other text)|
|South East or Southeast||S.E. or SE (use only in street addresses, not in other text)|
|South West or Southwest||S.W. or SW (use only in street addresses, not in other text)|
|Street||St. or St|
|West||W. or W (use only in street addresses, not in other text)|
|Association||Assn. or Assn|
|Doing business as||d.b.a. or DBA|
|Limited||Ltd. or Ltd|
|Limited liability company (or partnership)||LLC (LLP)|
|Public limited company||PLC|
|Manufacturing||Mfg. or Mfg|
|Publishing||Pubg. or Pubg|
|Publications||Pub., Pubs., Pubs|
|University||Univ., U. or Uni.|
|Academic degrees, military ranks, professional titles, etc.|
|Bachelor of Arts (Artium Baccalaureus)||BA or AB|
|Bachelor of Laws (Legum Baccalaureus)||LLB|
|Bachelor of Science||BS or BSc|
|Colonel||Col. or Col|
|Commander||Cmdr., Cmdr, Cdr or Comdr|
|Corporal||Cpl. or Cpl|
|Doctor||Dr. or Dr|
|Doctor of Medicine (Medicinæ Doctor)||MD|
|Doctor of Philosophy (Philosophiæ Doctor)||PhD|
|Right Honourable||Rt. Hon. or Rt Hon.|
|Junior||Jr. or Jr (use the format "Firstname Lastname, Jr." in article titles)|
|Lieutenant||Lt. or Lt|
|Monsignor||Mons., Msgr. or Msgr|
|Saint||St. or St|
|Senior||Sr. or Sr (use the format "Firstname Lastname, Sr." in article titles)|
|Sergeant||Sgt. or Sgt|
|Master sergeant||MSgt. or MSgt|
|Staff sergeant||SSgt. or SSgt|
|Technical sergeant||TSgt. or TSgt|
Special considerations 
- Postal codes and abbreviations of place names (e.g. Calif. (California), TX (Texas), Yorks (Yorkshire) should not be used to stand in for the full names in normal text. The practice is common when specifying places of publication in source citations, especially after the first occurrence.
- "Saint" vs "St" or "St." in placenames should depend upon the official usage.
- Abbreviations should be written in the same fashion each time they are used within the same page (e.g. "US" and "U.S." should not be alternated). Any special cases should have a natural reason (perhaps a list of officers in a joint British–American taskforce) that should be obvious to the reader; stating such a reason in a hidden note will help other editors to maintain it.