This page documents an English Wikipedia style guideline. It is a generally accepted standard that editors should attempt to follow, though it is best treated with common sense, and occasional exceptions may apply. Any substantive edit to this page should reflect consensus. When in doubt, discuss first on the talk page.

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When writing technical (scientific, medical, legal, etc.) articles, it is usually the case that a number of technical terms or terms of art and jargon specific to the subject matter will be presented. These should be defined or at least alternative language provided, so that a non-technical reader can both learn the terms and understand how they are used by scientists. It is also the case that such an article can cover a range of related subjects that might not each justify a separate article or Wikipedia page, and therefore making technical terms stand out in the text is the first level in a sequence from definition to subtitle to separate article. On the other hand, do not treat every “scientific” word as a technical term. Ask the question: Is this the only article or one of a very few where the term might be encountered in Wikipedia? Consider the examples presented below.

There are three basic markups used to make technical terms stand out; these are italic (in typography also termed oblique with regard to sans-serif fonts), bold, and bold italic. The following uses of these styles are recommended for technical articles:

Italic (edited as ''italic'') is used for:

• Words of foreign languages, other than established loan words: "hidari" (Jp: "left"); but not "gauche" (Fr: "left"), an established loan word in English.
• Binomial names of organisms (Genus species), which are considered Latin, even if newly coined. (The initial letter of a genus is always capitalized, but never that of a species.) Higher taxonomic levels are not italicized. When both the classification term and its name form a unified title, they are both first-letter capitalized: "Family Poaceae"; when they do not form a title, only the name is capitalized: "the family Poaceae".
• Technical or scientific terms that are defined above in the same article (and appear there in bold italic; see below) to demonstrate use of the term, or emphasize that use to the reader. Although it is standard practice in text books to put in italics or bold font those words likely to be new to the reader only the first time the word appears, it is helpful to the learning process if newly defined terms that reappear are rendered in italic font elsewhere in a Wikipedia article.
• Terms that are not defined at that point in the text, but are nonetheless "technical", although will likely appear in numerous other articles in Wikipedia. Here, the "emphasize only the first time used on a page" rule could apply. Example (from Plant):

Groups at this level of organization, collectively called bryophytes, include….

• Words as words: Deuce means two, or "deuce" means "two", whichever will be clearer in context (consider an article with many quotations, or an article full of italicized foreign terms). See Wikipedia:Manual of Style: "Words as words" subsection for more information.
• Legal case names are always italicized: Plessy v Ferguson.
• See also Wikipedia:Manual of Style: "Captions" subsection and Wikipedia:Cite your sources for other uses of italicized text.

Bold (edited as '''bold'''); used for:

• First use of the article name, near the front of the introduction sentence.
• Definitions that are important aspects discussed by the article, but have not been elevated to the level of subtitle and do not pass the "rare technical term" test. Example (from Current (electricity)):

In electricity, current is any flow of charge, usually through a metal wire or some other electrical conductor. Conventional current was defined early in the history of electrical science as a flow of positive charge, although we now know that, in the case of metallic conduction...

Bold italic (edited as '''''bold italic'''''); used for:

• First time introduction of a technical term if the term is immediately followed by a non-technical substitute in parentheses. Example (from Fern):

A fern is defined as a vascular plant that reproduces by shedding spores to initiate an alternation of generations. New fronds arise by circinate vernation (unrolling leaf formation).

As in the fern example above, any of the three styles described above could be turned into a link if there exists a more detailed or better explanation of the technical term in a separate article. It may not be necessary then to define the term in the article if a link leads to a definition. However, to aid the reader in continuing with the text without having to leave an article for other details, it might still be appropriate to include a non-technical substitute in parentheses, as in the fern example above.

When a vast amount of jargon appears in an article, you might consider bundling all terms and their definitions within a glossary. When you do so, do use the appropriate definition list markup:

Instead of

*'''term''': definition

use

; term : definition

Wikipedia uses "double quotation marks" (and for quotations within quotations, 'single quotation marks'), regardless of English-language variant. “Curly quotes” are not used in articles. See the "Quotation marks" subsection of the Manual of Style for more information.

[edit] See also

• Wikipedia:Explain jargon
• Wikipedia:Federal Standard 1037C terms
• Wikipedia:Make technical articles accessible