dfn element
If you don't know what an element is or how you must use it, I recommend you read the "HTML tags and attributes" tutorial that you can find in the HTML tutorials section.
Table of contents
Description
The dfn element represents a term that's supposed to be defined or described in the paragraph (p), section (section) or description list group (dl) where it's contained. Besides, references to a term inside dfn can be established with the a element.
The title attribute has a special meaning when used in this element. When present, it represents the term that's being described by the surrounding text overriding the element's contents.
When the only content of the dfn element is an abbreviation (abbr), the term to be defined is the content of the title attribute of the abbr element, unless dfn itself has a title attribute of its own.
Examples
In the following example we'll create a couple of paragraphs. In the first one, we'll define the term "Berlin wall" and we'll set the id attribute for the dfn element containing it. We'll do this to be able to establish a link to this term from other part of the document.
In the second paragraph, we'll be using the term again without defining it. Nevertheless, we'll make clear that this is the same term that's been defined previously, setting up a link to the id declared in the dfn element, thus linking both terms. For more information on how to set up this type of links, see the reference for the a element.
<p>The <dfn id="berlin-wall">Berlin wall</dfn> was a barrier constructed by the German Democratic Republic (GDR, East Germany) starting on 13 August 1961, that completely cut off (by land) West Berlin from surrounding East Germany and from East Berlin.</p>
<p>The Eastern Bloc claimed that the wall was erected to protect its population from fascist elements conspiring to prevent the "will of the people" in building a socialist state in East Germany. In practice, the <a href="#berlin-wall">Berlin wall</a> served to prevent the massive emigration and defection that marked East Germany and the communist Eastern Bloc during the post-World War II period.</p>
The Berlin wall was a barrier constructed by the German Democratic Republic (GDR, East Germany) starting on 13 August 1961, that completely cut off (by land) West Berlin from surrounding East Germany and from East Berlin.
The Eastern Bloc claimed that the wall was erected to protect its population from fascist elements conspiring to prevent the "will of the people" in building a socialist state in East Germany. In practice, the Berlin wall served to prevent the massive emigration and defection that marked East Germany and the communist Eastern Bloc during the post-World War II period.
In the next example, the content of the dfn element is an abbreviation (abbr). Therefore, and as seen in the description, the content of the title attribute ("Cascading Style Sheets") of the abbr element will be the term defined in the containing paragraph.
<p><dfn><abbr title="Cascading Style Sheets">CSS</abbr></dfn> is a style sheet language used for describing the look of a document written in a markup language.</p>
CSS is a style sheet language used for describing the look of a document written in a markup language.
Attributes
Global attributes
For information about global attributes refer to this list of global attributes in HTML5.
Events
Global events
For information about global events refer to this list of global events in HTML5.