HTML abbr tag

The <abbr> tag defines an abbreviation or an acronym, like “HTML”, “CSS”, “Mr.”. Use the title attribute to show the description for the abbreviation when you mouse over the element:

<abbr title="Cascading Style Sheets">CSS</abbr>

<abbr> can also be used with <dfn> to define an abbreviation:

<p><dfn><abbr title="Cascading Style Sheets">CSS</abbr>
</dfn> describes the style of an HTML document.</p>

You can style abbr tag like this:

abbr {
  text-decoration: underline red dotted;
  color: red;
}

abbr:hover {
  cursor: help;
}

It is important to note that the abbr tag should only be used for abbreviations and acronyms that are commonly known, and not for every instance of an abbreviated term. Using the abbr tag too liberally can make your content more difficult to read and understand.