What is the definition of “the baseline of parent box”?

Question

I have trouble understanding the following excerpt from 10 Visual formatting model details – W3C.

The excerpt:

baseline: Align

Answer 1

Neither did I find a specific definition,and according to the specification:

The following values only have meaning with respect to a parent inline element, or to the strut of a parent block container element

You can infer that ,if there is a text node as child in the parent box ,the baseline of the child text node is the baseline of the parent box.

For example:

.parent {
  display: inline;
  background:pink;
  font-size:40px;
  font-family:Microsoft Yahei;
  line-height:2;
  vertical-align:baseline;
}
.element-child {
  font-size:25px;
}

   textNode child of parent 
  
    element-child with another font-size
  

Whatever with or without child text node,the baseline of parent box is in the same position which is equal to the baseline of the child text node.