An unordered list is a collection of items in which the order does not matter. Here is the syntax of an unordered list:

<ul>
  <li>...</li>
  <li>...</li>
</ul>

An ordered list is a collection of items where the order does matter. Here is the syntax of an ordered list:

<ol>
  <li>...</li>
  <li>...</li>
</ol>

Unstyled lists can be ordered or unordered with the removal of the left margin and the default list style. Here is the syntax of an unstyled list:

<ul class="list-unstyled">
  <li>...</li>
  <li>...</li>
</ul>

Inline lists arrange all items of a list into a single line or row. Here is the syntax of an inline list:

<ul class="list-inline">
  <li>...</li>
  <li>...</li> 
</ul>

A description list contains the list items along with their descriptions. Here is the syntax of a description list:

<dl>
  <dt>...</dt>
  <dd>...</dd>
</dl>

The horizontal description class does the same thing as the description list class with the only difference being the placement of the corresponding description of the list item in the same line. Here is the syntax of an horizontal description list:

<dl class="dl-horizontal">
  <dt>...</dt>
  <dd>...</dd>
</dl>