HTML <dfn> Tag

The <dfn> element in HTML is used to indicate the defining instance of a term. Essentially, it marks a word or phrase that is being defined within the context of the surrounding content. This element is particularly useful in documentation, glossaries, tutorials, or any content where a term needs to be introduced and clarified for readers.

When a term is wrapped in a <dfn> tag, it signals to browsers, assistive technologies, and search engines that the enclosed text represents a formal definition. This can improve semantic understanding of your content and potentially enhance accessibility. Additionally, by default, <dfn> is an inline element, meaning it does not create a line break before or after the term, allowing it to integrate seamlessly into paragraphs or sentences.

A common pattern is to pair <dfn> with an <abbr> or <span> element elsewhere in the text to create references or explanations, although this is optional. Typically, the first occurrence of a term is wrapped in <dfn> to indicate its definition, while subsequent uses may simply use normal text.

Example usage:

<p><dfn>HTML</dfn> stands for HyperText Markup Language and is the standard language for creating web pages.</p>

In this example, the <dfn> tag highlights “HTML” as the term being defined, making it semantically clear that this is the definition of that term.