The **`<abbr>`** tag is short for _abbreviation_. It is used to write an acronym or an abbreviation. 
# Syntax
```HTML
<abbr title="Full Form"> Abbreviation </abbr>

```

In the above snippet of code, the full form or detail of the abbreviation is passed as a string to the `title` attribute. 

When we hover the mouse over the abbreviation, the browser shows its full form. Some browsers display the abbreviations inline with the rest of the content, and some add a break automatically. A few browsers also underline the abbreviation with a dotted line.

# Examples
In the example below, _HTML_ is an abbreviation for Hypertext Markup Language. The full form of the abbreviation can be seen by hovering over it:

<!DOCTYPE html>
<html>
 
 <body>
 <abbr title="Hypertext Markup Language">HTML</abbr>
 is an abbreviation.
 </body>
 
</html>

codemirror

In the example below, the `<abbr>` tag is used twice. The full forms of the abbreviations can be seen by hovering over them:

<!DOCTYPE html>
<html>
 
 <body>
 The 
 <abbr title="United Nations General Assembly">UNGA</abbr>
 is one of the six principal organs of the 
 <abbr title="United Nations">UN.</abbr>
 </body>
 
</html>

What is the <abbr> element in HTML?

The `<abbr>` tag defines abbreviations or acronyms in HTML, revealing full forms on hover.