You'll sometimes want to include characters that aren't found on a typical keyboard, such as letters from foreign alphabets such as the Greek letter Δ, the Cyrillic letter И, the Hebrew letter א, or the Arabic letter ق. Latin letters with diacritical marks such as É, Ü, Ø, or Ç are other examples, as are mathematical symbols such as ≥ or ∞, arrows such as ↑ or →, and type symbols such as ¶ or § or —.
This tutorial describes the various methods to incorporate such symbols into your article.
Cut'n'paste
editThe simplest method is to cut and paste the symbol from one window to another. This works great if you're writing a series of articles, and the needed symbols recurs frequently. If it doesn't, this method is inefficient, because you have to fish through articles looking for your symbol.
Insert bar below the Edit summary
editOn the editing page, below the edit summary and the Save page/Show preview buttons, you'll find a slim horizontal bar that begins with the word "Insert" as shown here. To the left of Insert, you'll see various typographic symbols beginning with the en-dash – and em-dash —. (As an aside, notice that these are both bit longerthan the hyphen -.) Clicking on one of those symbols will add it to your article.
The "Insert" is a drop-down menu, allowing you to choose from several alphabets: "Latin", "Greek", "Cyrillic", "Hebrew", "Arabic", and "IPA". Each of these choices offers a different set of symbols that you might want to add to your article. The Latin menu gives many choices of letters with diacritical marks. "IPA" stands for the International Phonetic Alphabet.
HTML entities and the non-breaking space
editHTML entities are a method for incorporating special characters into webpages, not only on Wikipedia. These symbols take the general form &xxxx; where the "xxxx" stands for a set of letters or numbers. For example, the five characters & produces a single character &.
One especially important HTML entity is the non-breaking space, which is . This provides a space at which the browser will never break a line. They're used to keep two elements together such shouldn't be separated by a line break, such as the number and units of a scientific measurement. For example, the expression "42 furlongs" has a non-breaking space, and you'll see that the "42" and "furlongs" are moved together when the page is resized. It never happens that "42" sppears on one line, and "furlongs" appears on the next.