Boldface (text like this) is common in Wikipedia articles, but only for certain usages.

Article title terms

The most common use of boldface is to highlight the article title, and often synonyms, in the lead section (first paragraph). This is done for the majority of articles, but there are exceptions. See Lead section – Format of the first sentence for in-depth coverage.

Other uses

Use boldface in the remainder of the article only in a few special cases:

• Table headers and captions
• Description (definition, association) lists (example: Glossary of the American trucking industry)
• Mathematical objects traditionally written in boldface such as vectors and the rational numbers Q
• Volume numbers of journal articles, in some bibliographic formats

In the first two cases, the appropriate markup automatically adds the boldface formatting; do not use the explicit triple-apostrophe markup. Similarly, in the last case, the formatting should generally be added implicitly by use of a template, such as {{citation}}.

Contraindications

Use italics, not boldface, for emphasis in article text.

It is technically possible to bold non-Latin alphabets such as Greek or Cyrillic, but this should be avoided.

Wikipedia automatically puts sub- and sub-sub-headings (sub- and sub-sub-section titles) in boldface. Bolded headings, though technically possible, are not appropriate.

Italic type (text like this) has several uses on Wikipedia:

• Certain scientific names
  • Genes (but not proteins encoded by genes)
  • Genus and all lower taxa (including species and subspecies), but not higher taxa. The entire scientific name should be italicized, except where an author, "cf.", or some other interpolation is included in or appended to the name. (See §Scientific names for details.)
• Court case names (Case citation or law report information is presented in normal font.)
• Named vehicles
  • Ship classes—only when the class takes its name from a member of the class: USS Gearing (DD-710) is the lead ship of the Gearing class (See WP:SHIPMOS §Referring to ship classes)
  • Ship names—ship prefixes, classification symbols, and pennant numbers use normal font: USS Gearing (DD-710) (See WP:SHIPMOS §Referring to ships)
  • Trains and locomotives
• Works of art and artifice
  • Art exhibitions
  • Books
  • Cantatas and motets
  • Comic strips and webcomics
  • Computer and video games (but not other software)
  • Films (including short films) and documentaries
  • Long or epic poems
  • Musical albums
  • Musicals
  • Named orchestral works: Symphony No. 2 by Gustav Mahler, known as the Resurrection Symphony ...
  • Operas, operettas, oratorios
  • Paintings, sculptures and other works of visual art
  • Periodicals (newspapers, journals, and magazines)
  • Plays
  • Television and radio series and serials. But individual episodes of these should appear in quotes.

Abbreviations of the above should also be italicized.

Website titles may or may not be italicized depending on the type of site and what kind of content it features. Online magazines, newspapers, and news sites with original content should generally be italicized (Salon.com or The Huffington Post). Online encyclopedias and dictionaries should also be italicized (Scholarpedia or Merriam-Webster Online). Other types of websites should be decided on a case-by-case basis.

Emphasis

The use of italics for emphasis on Wikipedia should follow good English print style. The most accessible way to indicate emphasis is with HTML <em> tags or by enclosing the emphasized text within an {{em}} template. Italics may be used to draw attention to an important word or phrase within a sentence when the point or thrust of the sentence may otherwise not be apparent to readers, or to stress a contrast:

Gellner accepts that knowledge must be knowledge of something; and that some philosophical theories may arise from linguistic confusion.

It may be preferable to avoid the need for italics by rewriting a sentence more explicitly.

Italics may also be used where <dfn> tags or {{dfn}} templates mark a term's first use, definition, introduction, or distinguished meaning. Note that <dfn> tags and {{dfn}} templates do not apply text formatting. For instance, in the consciousness article:

Access consciousness is the phenomenon whereby information in our minds is accessible for verbal report and reasoning.

''<dfn>Access consciousness</dfn>'' is... or

{{em|{{dfn|Access consciousness}}}}

If, however, a term is strictly synonymous with the subject of the article, then bold face should be used in place of italics

<dfn style="font-weight: bold;">text</dfn> → text or

'''<dfn>text</dfn>''' → text

The first occurrence of a technical term may be both linked and italicized if the term also has its own article (or section) corresponding exactly to the meaning when used in the present article. A term being introduced is often mentioned as a word rather than playing its normal grammatical role; if so, it should be italicized or quoted, but not both.

Words as words

Use italics when writing about words as words, or letters as letters (to indicate the use–mention distinction). When italics would cause confusion, quotation marks may be used to distinguish words as words. For example:

• Deuce means "two".
• The term panning is derived from panorama, which was coined in 1787.
• The most common letter in English is e.

Foreign terms

Wikipedia prefers italics for phrases in other languages and for isolated foreign words that do not yet have everyday use in non-specialized English. Use the native spellings if they use the Latin alphabet (with or without diacritics)—otherwise Anglicise their spelling. For example: "Gustav I of Sweden liked to breakfast on crisp bread (knäckebröd) open sandwiches with toppings such as messmör (butter made from goat's milk), ham (skinka), vegetables (grönsaker) like tomatoes (tomat) or cucumber (gurka)." In accordance with the guide to writing better Wikipedia articles, use foreign words sparingly.

Loanwords or phrases that have common use in English, however—praetor, Gestapo, samurai, esprit de corps, e.g., i.e.—do not require italicization. Likewise, musical movement titles, tempo markings, or terms like minuet and trio, are in normal upright font. If looking for a good rule of thumb, do not italicize words that appear in Merriam-Webster Online.

If there is a reason to include a term in a non-Latin script, it can be placed in parentheses. Text in non-Latin scripts (such as Greek, Cyrillic or Chinese) should not be italicized at all—even where this is technically feasible; the difference of script suffices to distinguish it on the page.

A proper name is usually not italicized when it is used, but it may be italicized when the name itself is being referred to (see Words as words).

For better accessibility, Latin quotations should never be set in all caps or small caps, even when the use of lowercase might seem anachronistic. (Please note, however, that simply undoing caps may result in incorrect orthography; for example, capital V, when used as a vowel, is equivalent to u, not v.)

Scientific names

Scientific names of organisms are formatted according to normal taxonomic nomenclature.

• do not italicize (but do capitalize) taxa higher than genus
• italicize all lower ranks (taxa): genus (capitalized), subgenus (capitalized), species, subspecies
  • names of genera are always italicized (and capitalized), even when not paired with a species name: Allosaurus, Falco, Anas
  • The entire binomial or trinomial scientific name is italicized, whether given in full or abbreviated: (Liriodendron tulipifera, N. v. piaropicola)
• interpolations such as "cf." or "×" are not italicized: Ninox cf. novaeseelandiae, the chaussie is a hybrid cat (Felis catus × F. chaus)
• parenthetic expressions should not be italicized unless part of the scientific name, as in the case of a subgenus, which is always italicized, though the parentheses (round brackets) are not: Potentilla (Sibbaldiopsis) tridentata
• do not italicize author names juxtaposed with scientific names: Subgenus Potentilla Syme and subgenus Hypargyrium (Fourr.) Juz. have been combined under subgenus Potentilla Syme

Derived uses in non-biological contexts are not italicized: The largest carnivore in family Tyrannosauridae was T. rex itself, but Unicorn was an album by the band T. Rex.

Although derived from Latin (and often Ancient Greek) scientific names are never marked up with {{lang}} or related templates.

Quotations

It is normally incorrect to put quotations in italics. They should only be used if the material would otherwise call for italics, such as for emphasis or to indicate use of non-English words. Indicate whether italics were used in the original text or whether they were added later. For example:

Now cracks a noble heart. Good night sweet prince: And flights of angels sing thee to thy rest!

(emphasis added)

Variables

Program variables

Variables in computer programs and symbols for program variables within plain-English prose and in computer source code presented as textual content can be marked up with the <var> element, or its wikimarkup equivalent, the {{var}} template:

• ...where <var>x</var> is incremented on each pass... ⇒ ...where x is incremented on each pass...
• |id={{var|ISBN or other identifier}} ⇒ |id=ISBN or other identifier

This provides richer semantic markup over simple italicization (or no formatting at all), that can aid in searching, accessibility, and disambiguation between variables and literal values.

Mathematics variables

Symbols for mathematics variables, either used within mathematical formulas or used in isolation, are simply italicized:

• The value of ''y'' when ''x'' = 3 ⇒ The value of y when x = 3
• ''E'' = ''m''c<sup>2</sup> ⇒ E = mc²

Some things remain in upright form regardless of the surrounding text

• Bold-face variables (such as vectors) and structures (such as Q, the rational numbers)
• Letters with an arrow on top for vectors
• Symbols for chemical elements and compounds such as HCl
• Symbols for units of measure such as kg, ft/s
• Symbols for mathematical operators such as sin and ln

  sin x, ln (p/p₀)

The template {{varserif}} is available to distinguish between I (upper-case i) and l (lower-case L) as variables, which look almost identical in most sans-serif fonts, including the default typefaces of many browsers.

Uses of italics that are specific to Wikipedia

One-line notes that are placed at the top of articles or sections to assist disambiguation are hatnotes. One-line notes may also be placed at the top of sections to cross-reference or point to additional information that is not directly linked in the text. Both of these are in italics and indented, in order to distinguish them from the text of the article proper. Using the correct Disambiguation and redirection templates or Wikipedia page-section templates automatically provides the required italic formatting.

Special section headings for appendices such as ==See also== are not in italics.

A further type of cross-reference may occur within a paragraph of text, usually in parentheses. For example:

At this time France possessed the largest population in Europe (see Demographics of France).

Unlike many traditional reference works, the convention on Wikipedia that has evolved is that "see" or "see also" are not in italics. Nor are the article titles put in quotation marks.

When not to use italics

Italics are generally used only for titles of longer works. Titles of shorter works should be enclosed in double quotation marks ("text like this"). This particularly applies to works that exist as a smaller part of a larger work. Examples of titles which are quoted:

• Articles, essays or papers
• Chapters of a longer work
• Entries in a longer work (dictionary, encyclopedia, etc.)
• Single episodes of a television series
• Short poems
• Short stories
• Arias, musical numbers, songs, and "singles"
• Foreign-language text in non-Latin-1 scripts, such as Chinese characters

Avoid various kinds of overemphasis, which distracts from the writing:

• Exclamation points (!) should usually only be used in direct quotes.
• Bold type is reserved for certain uses (see boldface, above).
• Quotation marks for emphasis of a single word or phrase, or scare quotes, are discouraged. Quotation marks are to show that you are using the correct word as quoted from the original source. For example: His tombstone was inscribed with the name "Aaron" instead of the spelling he used during his life.
• Avoid using ALL CAPS and small caps for emphasis; see All caps. Italics are usually more appropriate.
• Double emphasis, such as "italics in quotation marks" or italics and an exclamation point!, is unnecessary.
• Underlining is used in typewriting and handwriting to represent italic type. Generally, do not underline text or it may be confused with links on a web page.

Font size

Editors should avoid manually inserting large and small fonts into prose. Increased and decreased font size should primarily be produced through automated facilities such as headings or through carefully designed templates. Additionally, large tables may require a decreased font size in order to fit on screen.

When it is necessary to specify an increased or decreased font size, the specification should be done as a percentage of the original font size and not as an absolute size. This improves accessibility for visually impaired users who use a large default font size.

Color

In prose

Prose text should never be manually colored. Links should clearly be identifiable as a link to our readers. Further information can be found at Wikipedia:Accessibility#Color.

In navboxes

1. Keeping in line with Wikipedia:Manual of Style/Accessibility#Color, colors used in navboxes should not make navigating difficult for colorblind or visually impaired readers.
2. Colors that are useful for identification and are appropriate, representative, and accessible may be used with discretion and common sense. In general, text color should not be anything other than black or white (excluding the standard colors of hyperlinks), and background colors should contrast the text color enough to make the template easily readable.
3. An "appropriate, representative" color, when intended to identify with an organization's logo or branding, should use the most prominent accessible color in the logo. For example, Template:Pink Panther should be using a background of F6D4E6   (the color of the body in File:Pink Panther.png) rather than E466A9   (the color of the background in that image). A representative color may also be the one present in an article's infobox (if included). For example the navbox associated with National Register of Historic Places (NRHP)s and other related categorizations should conform to Wikipedia's NRHP colors legend.
4. In the case that no properly identifying, accessible color exists; or the subject of the navbox should not be identified with a particular color (e.g. an average biography), the default navbox color should be used.
5. If an article includes several navboxes whose colors conflict with each other, discretion should be used to minimize the disruption by using the default colors for navboxes.

Font family

Font families should not be explicitly defined in the CSS of an article. On one hand, this interferes with Wikipedia's flexibility. On the other hand, it is impossible to foresee what fonts will be installed on a user's computer.

Articles used to explicitly define font families for special characters, because older browsers could not automatically select an appropriate font. This is no longer dealt with by using explicit font definitions in the articles. Instead, the font definitions have been moved to MediaWiki:Common.css/WinFixes.css. These definitions are invoked by using special templates, see Help:Special characters, {{unicode}} or {{IPA}}.

Mixed right-to-left text

When right-to-left text is embedded in certain left-to-right contexts, such as when tagged with a reference, it may require invisible control characters to display properly. However, because such characters are not visible in the edit window, are often inserted inadvertently by pasting from a word processor, and can cause confusion with editors and handling problems with editing software, the actual character should not be used. (If it is used, it may be flagged as CHECKWIKI error 16 and removed by a bot.) The marker to return to left-to-right text should instead be substituted with the code ‎ or supplied through the template {{Rtl-lang}}.

Compare the display of unformatted Urdu

خ ?<ref>(note)</ref>:   خ ?^[1]

with formatted

خ&lrm; ?<ref>(note)</ref>:   خ‎ ?^[1] or {{Rtl-lang|ur|خ}} ?<ref>(note)</ref>:   Template:Rtl-lang ?^[1]

and unformatted

(خ)<ref>(note)</ref>:   (خ)^[1]

with formatted

(خ)&lrm;<ref>(note)</ref>:   (خ)‎^[1] or {{Rtl-lang|ur|(خ)}}<ref>(note)</ref>:   Template:Rtl-lang^[1].

If there is intervening LTR text, as in خ abc[1], a control character is not required. Spacing and most punctuation, however, are not defined as either LTR or RTL, and so do not reset the direction of the text.

• Wikipedia:Manual of Style/Capital letters
• Wikipedia:Manual of Style/Command-line examples
• Wikipedia:Stop bolding everything (essay)