Syntax
<p><dfn>Hoisting</dfn> is JavaScript's behavior of moving declarations to the top of scope.</p>Examples
Defining a Technical Term
Introducing and defining a term the first time it appears.
<p>A <dfn>closure</dfn> is a function bundled together with references to its surrounding state.</p>Defining Term with a Title Attribute
Adding a short definition as a tooltip.
<p><dfn title="A reusable block of code that performs a task">Function</dfn> declarations start with the function keyword.</p>Best practices
- Use <dfn> only at the point where a term is actually being defined, not every time it is mentioned afterward
- Combine with a title attribute or nearby explanation so the definition is genuinely available, not just implied by italics
- Consider pairing with a glossary section using a definition list for a list of defined terms
- Do not use dfn purely for italic styling on unrelated text
At a glance
- Purpose
- Structure and meaning for web content
- File extension
- .html · .htm
- Runs in
- Web browsers
- Usually used with
- CSS and JavaScript
Specifications & further reading
Related HTML documentation
<span>
The <span> element is an inline container used to group and style specific portions of text or inline elements. Unlike <div>, which is block-level, <span> doesn't break the flow of content. It's perfect for applying styles or manipulating specific words or phrases within a paragraph without affecting the surrounding content.<h1> - <h6>
The heading elements <h1> through <h6> represent six levels of section headings, with <h1> being the most important and <h6> the least. Headings create a document outline that both sighted users and assistive technologies rely on to understand and navigate page structure. Search engines also use heading hierarchy to interpret content relevance. Each page should typically have exactly one <h1> describing its main topic, with subsequent headings nested logically to reflect the content hierarchy.<p>
The <p> element represents a paragraph of text — one of the most fundamental building blocks of written content on the web. Browsers automatically add margin above and below paragraphs to visually separate them. The <p> element cannot contain other block-level elements like <div> or headings, only inline content and text. It is a block-level element, meaning it always starts on a new line.Text Formatting: <strong>, <em>, <b>, <i>, <mark>, <small>
HTML provides several inline elements for formatting text with semantic and visual meaning. <strong> indicates strong importance (typically rendered bold), and <em> indicates stress emphasis (typically rendered italic) — both carry semantic weight that screen readers can announce. <b> and <i> are their purely visual counterparts, used when bold/italic styling is needed without implying importance or emphasis. <mark> highlights text as relevant to the current context, and <small> represents side comments like fine print or disclaimers.
The <span> element is an inline container used to group and style specific portions of text or inline elements. Unlike <div>, which is block-level, <span> doesn't break the flow of content. It's perfect for applying styles or manipulating specific words or phrases within a paragraph without affecting the surrounding content.<h1> - <h6>
The heading elements <h1> through <h6> represent six levels of section headings, with <h1> being the most important and <h6> the least. Headings create a document outline that both sighted users and assistive technologies rely on to understand and navigate page structure. Search engines also use heading hierarchy to interpret content relevance. Each page should typically have exactly one <h1> describing its main topic, with subsequent headings nested logically to reflect the content hierarchy.<p>
The <p> element represents a paragraph of text — one of the most fundamental building blocks of written content on the web. Browsers automatically add margin above and below paragraphs to visually separate them. The <p> element cannot contain other block-level elements like <div> or headings, only inline content and text. It is a block-level element, meaning it always starts on a new line.Text Formatting: <strong>, <em>, <b>, <i>, <mark>, <small>
HTML provides several inline elements for formatting text with semantic and visual meaning. <strong> indicates strong importance (typically rendered bold), and <em> indicates stress emphasis (typically rendered italic) — both carry semantic weight that screen readers can announce. <b> and <i> are their purely visual counterparts, used when bold/italic styling is needed without implying importance or emphasis. <mark> highlights text as relevant to the current context, and <small> represents side comments like fine print or disclaimers.