Abbreviation is a formatting element used to define abbreviation. It is used to provide information to viewer, abbrivation text is different from other text because is underlined by dotted line and it defines any acronym.
<abbr title=Some information
>Content</abbr>
OR
<tag><abbr title=Some information
>Content</abbr></tag>
You can apply abbrivation element to any element and use any where within a HTML document.
Abbr is a pair tag and output of abbr element is dotted underlined text like you can see in above example.
when you hover over abbr text it will show you information about abbreviation.
Open notepad or any other text editor, follow the following points.
save file with name task.html or task.htm and then open it using any browser and see results.