The “ > “ greather symbol is the child combinator, and “selects elements direct descendants of the previous specified element”.
ol > li {
color: red;
}<ol>
<li>WILL be selected</li>
<li>WILL be selected</li>
<ul>
<li>Will NOT be selected</li>
<li>Will NOT be selected</li>
</ul>
<li>WILL be selected</li>
</ol>The “ + “ plus symbol is the adjacent sibling combinator, and “selects elements direct descendants after of the previous specified element (with nothing in between)”.
ol + li {
color: red;
}<ol>
<li>WILL be selected</li>
<li>WILL be selected</li>
<br />
<li>Will NOT be selected</li>
<li>Will NOT be selected</li>
</ol>Article from css-tricks.com