MultiMarkdown includes support for abbreviations, as implemented in Michel Fortin’s PHP Markdown Extra. Basically, you define an abbreviation using the following syntax:

*[HTML]: HyperText Markup Language
*[W3C]:  World Wide Web Consortium

Then, wherever you use the words HTML or W3C in your document, the abbr markup will be added:

The HTML specification
is maintained by the W3C.


The <abbr title="Hyper Text Markup Language">HTML</abbr> specification
is maintained by the <abbr title="World Wide Web Consortium">W3C</abbr>.

Here’s an example using HTML and W3C. The exact behavior will depend on which format you are viewing this document in. Especially if we use HTML and W3C again. (Remember that HTML has probably already been used if you’re viewing a longer version of this document.)

As in PHP Markdown Extra, abbreviations are case-sensitive and will work on multiple word abbreviations. In this case, MultiMarkdown is tolerant of different variations of whitespace between words.

Operation Tigra Genesis is going well.

*[Tigra Genesis]:

An abbreviation with an empty definition results in an omitted title attribute.

There are a few limitations: