Nested lists defines list inside an other list like you can place unordered list inside an other unordered list or you can place ordered list inside unordered list.
<ul>
<li>Item 1</li>
<li>Item 2
<ul>
<li>Item 2.1</li>
<li>Item 2.2</li>
</ul>
</li>
<li>Item 3</li>
</ul>
You can use nested lists any where within an HTML document.
You can create navigation bar or dropdown lists using nested lists.
Nested lists are pair tags and output of nested lists is lists of elements like you can see in above example.
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.
Nested lists are combination of ol lists, ul lists and dl lists.