What is this > in CSS? [duplicate]

This question already has an answer here:

• What does the “>” (greater-than sign) CSS selector mean? 7 answers

I saw this > in css foundation template and I would like to know what that means

medium-cell-block-container > .grid-x {
      max-height: 100%;
      -ms-flex-wrap: nowrap;
          flex-wrap: nowrap; }