With the video and unordered list elements, you may have noticed something interesting: these HTML elements had other HTML elements nested inside of them.

For example, in unordered lists, li elements are nested inside the ul.

<ul>
  <li>First item</li> 
  <li>Second item</li>
</ul>

Web developers refer to the enclosing element as the parent element and the enclosed elements as children.

Referring to HTML elements as parents and children may sound funny, but it’s a core web development concept. The web browser also knows about these parent/child relationships, which will be important as we explore CSS in the next lesson.