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HTML <dfn> Tag


The <dfn> tag in HTML is used to mark up a term that’s being defined within the context of a definition expression. It’s a way to highlight the defining instance of a term. The nearest parent element of the <dfn> tag that has a title attribute explains the term. The content inside the <dfn> tag is typically rendered in italic by browsers.


Example 1: Marking Up a Term with <dfn>

Here’s an example of how you can use the <dfn> tag to mark up a term:

<dfn>HTML</dfn> is a standard markup language for documents designed to be displayed in a web browser.


Example 2: Using the Title Attribute with <dfn>

You can also use the title attribute with the <dfn> tag to provide a definition:

<dfn title="HyperText Markup Language">HTML</dfn> is used to structure content on the web.

Example 3: Using an <abbr> Tag Inside the <dfn> Element

You can include an <abbr> tag inside the <dfn> element to define an abbreviation:

<dfn><abbr title="Cascading Style Sheets">CSS</abbr></dfn> is a stylesheet language used for describing the look and formatting of a document written in HTML.

Try it out below:



Global Attributes

The <dfn> tag supports all the global attributes in HTML.

Event Attributes

The <dfn> tag also supports all the event attributes in HTML.

Browser Support

Browser Support
Chrome Yes
Firefox Yes
Safari Yes
Opera Yes
IE Yes

Default CSS Settings

Most browsers will display the <dfn> element with the following default CSS settings:

dfn {
  font-style: italic;


The <dfn> tag provides a semantic way to highlight the defining instance of a term within a definition expression.

It’s useful for authors, educators, and content creators who want to emphasize specific terms and their definitions.