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.

Shortcuts: MOS:ABBR WP:ABBR WP:MOSABBR

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For a directory of all the abbreviations used on Wikipedia, see Wikipedia:Wikipedia abbreviations.

For abbreviated redirects to non-main namespaces, see Wikipedia:List of shortcuts.

For abbreviations used by Wikipedians in discussion on talk pages and other non-article pages, see Wikipedia:Glossary.

This guideline covers the use of abbreviations, including acronyms and initialisms, 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, initialism, or contraction. In the case of an initialism 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., not New York is in the U.S..).

Acronyms and initialisms

See also: Wikipedia:Manual of Style (capital letters)#Acronyms and initialisms

Acronyms and initialisms are abbreviations formed, usually, from the initial letters of words in a phrase; the difference being acronyms are pronounced as the word is spelled (e.g. NATO), whereas with initialisms, each letter is pronounced individually (e.g. ABC).

• 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). All initialisms are written in capitals.
• Spacing: The letters of acronyms and initialisms should not be spaced.
• Plurals: Plural acronyms and initialisms 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).

Unless specified in one of the two tables below, an acronym or initialism should be written out in full the first time it is used on a page, followed by the abbreviation in brackets (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 and initialisms do not need to be written out in full. When not written out in full on the first use on a page, an acronym or initialism should be linked. An unambiguous acronym can be linked as is but an initialism or ambiguous acronym should be linked to its expansion.

Acronym exceptions

Acronyms on this table do not need to written out in full the first time they are used on a page, except in their own articles or if not doing so would cause ambiguity. They should only be linked to their expansion if their article is named that way.

Acronym	Expansion
AIDS	acquired immunodeficiency syndrome
ANZAC	Australian and New Zealand Army Corps
laser	light amplification by stimulated emission of radiation
NASA	National Aeronautics and Space Administration
NATO	North Atlantic Treaty Organization
quango	quasi-autonomous non-governmental organization
radar	radio detection and ranging
scuba	self-contained underwater breathing apparatus
sonar	sound navigation and ranging
UNESCO	United Nations Educational, Scientific and Cultural Organization
UNICEF	United Nations Children's Fund

Initialism exceptions

Ship names

Main page: Wikipedia:Naming conventions (ships)

Abbreviations in the names of ships (e.g. HMS and USS) should not be written out in full in the names of ships.

Time zones

Abbreviations for time zones (e.g. GMT and UTC) should not be written out in full in times.

Miscellaneous initialisms

Initialism	Expansion	Notes
AD	Anno Domini (English: in the year of our lord)	AD 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.
AKA	also known as	AKA should only be used in small spaces. It does not need to be linked.
AM	amplitude modulation	AM does not need to be written out in full on first use.
am	ante meridiem	The initialism am should not be written out in full in times and does not need to be linked. It should not be written AM.
BBC	British Broadcasting Corporation	BBC does not need to be written out in full on first use.
BC	Before Christ	BC should not be written out in full in dates and does not need to be linked.
BCE	Before Common Era	BCE should not be written out in full in dates.
c.	circa (English: around)	Use c. only for dates in small spaces and in the opening sentence of a biography (see MOS:DOB). It should not be italicised in normal usage. Do not use ca.
CD	Compact Disc	CD does not need to be written out in full on first use.
CE	Common Era	CE should not be written out in full in dates.
DVD	Digital Versatile Disc	DVD should not be written out in full and should not be linked to its expansion.
e.g.	exempli gratia (English: for example)	The abbreviation for the Latin phrase exempli gratia should not be italicised in normal usage. It should not be followed by a comma.
FM	frequency modulation	FM does not need to be written out in full on first use.
HIV	human immunodeficiency virus	HIV does not need to be written out in full on first use.
i.e.	id est (English: that is / in other words)	The abbreviation for the Latin phrase id est should not be italicised in normal usage. It should not be followed by a comma.
N/A	not applicable	N/A should not be written n/a, NA or na.
PC	personal computer	PC does not need to be written out in full on first use.
pm	post meridiem	The initialism pm should not be written out in full in times and does not need to be linked. It should not be written PM.
TV	television	The abbreviation for television does not need to be provided in brackets on first use.
UAE	United Arab Emirates	The abbreviation for United Arab Emirates does not need to be provided in brackets on first use.
UK	United Kingdom	The abbreviation for United Kingdom does not need to be provided in brackets on first use.
U.S. or US	United States	The abbreviation for United States does not need to be provided in brackets on first use. USA and U. S. of A. should not be used.
USB	Universal Serial Bus	USB does not need to be written out in full on first use.
USSR	Union of Soviet Socialist Republics	USSR does not need to be written out in full on first use.

Acronyms and initialisms in page titles

Shortcut: WP:ACRONYMTITLE

See also: Wikipedia:Article titles#Article title format

An acronym or initialism should be used in a page name if the subject is almost exclusively known by its acronym or is widely known and used in that form (e.g. NASA and radar). 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 and initialisms 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 or initialism 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 and initialisms as disambiguators

To save space, acronyms and initialisms 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.

To help navigation, please create redirects that contain (US) and (U.S.). For example, "Great Northern Railway (US)" should redirect to "Great Northern Railway (U.S.)" (or the other way around).

Acronyms and initialisms in category names

For discussion on the use of acronyms in names of categories, see Wikipedia talk:Naming conventions (categories)/Archive 7#Abbreviations: to expand or not to expand?.

Contractions

Further information: Wikipedia:List of English contractions

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).)

Initials

The main section for this topic is on the page Wikipedia:Naming conventions (people), in the section Middle names and abbreviated names.

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 ( ).

Shortenings

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, should be avoided. Uncommon shortenings should be linked on the first use on a page.

Song-writing credits

Outside of prose, trad. and arr. may be used in song-writing credits to save space. On first usage, use {{trad.}} and {{arr.}}.

Miscellaneous shortenings

Shortening	Expansion	Notes
approx.	approximately	It should only be used in small spaces. It does not need to be linked.
cf.	confer (English: compare/consult)	It should be linked on first use.
Co.	Company	It should only be used in the names of companies. 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 (English: and others)	It should only be used in references.
fl.	floruit (English: flourished)	It should be linked on first use. Do not use flor. or flr.
pub.	publisher	It should only be used in references. It does not need to be linked.
rev.	revised	It should only be used in references. It does not need to be linked.
v./vs	versus (English: against / in contrast to)	They do not need to be linked.
viz.	videlicet (English: that is to say / namely)	It should be linked on first use.

Symbols

Unit symbols

The main section for this topic is on the page Wikipedia:Manual of Style, in the section Unit names and symbols.

Miscellaneous symbols

• Ampersands (&) should only be used in small spaces, but, preferably, should be avoided.
• 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.

Do not use &c. in the place of etc.

The initialisms "e.g." and "i.e." should not be followed by a comma.

Widely used abbreviations in Wikipedia

In Wikipedia, abbreviations for common terms are often contained in parentheses within the head paragraph. 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).

Word(s)	Abbreviation
Places
Avenue	Ave. or Ave
Boulevard	Blvd
Crescent	Cr.
Close	Cl.
Highway	Hwy
Motorway	Mwy
Mountain/Mount	Mt or Mt.
Road	Rd
Street	St. or St
Organizations
Academy	Acad.
Association	Assn
Corporation	Corp.
Incorporated	Inc.
Institute/Institution	Inst.
Limited	Ltd
Public limited company	PLC, plc or p.l.c.
University	Univ., U. or uni
Academic degrees, titles and ranks
Bachelor of Arts (Artium Baccalaureus)	BA or A.B.
Bachelor of Laws (Legum Baccalaureus)	LLB or LL.B.
Bachelor of Science	BS, BSc or B.Sc.
Captain	Capt.
Colonel	Col. or Col
Commander	Cmdr, Cdr or Comdr
Corporal	Cpl
Doctor	Dr
Doctor of Medicine (Medicinæ Doctor)	MD
Doctor of Philosophy (Philosophiæ Doctor)	PhD or Ph.D.
General	Gen.
Honorable	Hon.
Junior	Jr
Lieutenant	Lt or Lt.
Monsignor	Msgr or Mons.
registered nurse	RN
Reverend	Rev.
Right Honourable	Rt. Hon. or Rt Hon
Saint	St
Senior	Sr
Sergeant	Sgt
Staff Sergeant	SSgt
Technical Sergeant	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.
• "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 Anglo-American taskforce) that should be obvious to the reader; stating such a reason in a hidden note will help other editors to maintain it.

See also

• American and British English differences#Punctuation
• Wikipedia:Edit summary legend
• Wikipedia:Manual of Style#Acronyms and abbreviations
• Wikipedia:Naming conventions (aircraft)
• Wikipedia:Naming conventions (ships)