E:only-child

Matches an E element, that is the only child of its parent. (Source: W3C)

HTML:

1. <div>
2. <p>Lorem ipsum dolor sit amet, consectetur</p>
3. <p>Lorem ipsum dolor sit amet, consectetur</p>
4. </div>
5. <div>
6. <p>Lorem ipsum dolor sit amet, consectetur</p>
7. </div>

CSS:

1. p:only-child{font-style:italic}

Output:

In the example, the third line of text should be set in italics as it is the only element in its parent element.