From http://www.w3schools.com (Copyright Refsnes Data)

HTML <em> <strong> <dfn> <code> <samp> <kbd> <var> <cite> tags

Example

Format text in a document:

<em>Emphasized text</em>
<strong>Strong text</strong>
<dfn>Definition term</dfn>
<code>Computer code text</code>
<samp>Sample computer code text</samp>
<kbd>Keyboard text</kbd>
<var>Variable</var>
<cite>Citation</cite>

Try it yourself!

Definition and Usage

The <em>, <strong>, <dfn>, <code>, <samp>, <kbd>, <var>, and <cite> tags are all phrase tags. They are not deprecated, but it is possible to achieve richer effect with CSS.

<em> Renders as emphasized text
<strong> Renders as strong emphasized text
<dfn> Defines a definition term
<code> Defines computer code text
<samp> Defines sample computer code
<kbd> Defines keyboard text
<var> Defines a variable
<cite> Defines a citation

Browser Support

Internet Explorer Firefox Opera Google Chrome Safari

The <em>, <strong>, <dfn>, <code>, <samp>, <kbd>, <var>, and <cite> tags are supported in all major browsers.

Differences Between HTML and XHTML

NONE

Standard Attributes

id, class, title, style, dir, lang, xml:lang

For a full description, go to Standard Attributes.

Event Attributes

onclick, ondblclick, onmousedown, onmouseup, onmouseover, onmousemove, onmouseout, onkeypress, onkeydown, onkeyup

For a full description, go to Event Attributes.

From http://www.w3schools.com (Copyright Refsnes Data)