"Instead of nesting definitions" in docs

On this page: https://react.dev/learn/your-first-component

When a child component needs some data from a parent, pass it by props instead of nesting definitions.

all of a sudden, it says, "instead of nesting definitions". Can you explain in the docs more what is "nesting definitions" and how does it work to "attempt to pass some data and doesn't work or shouldn't be done"? I have never heard of "nesting definitions" after working with React for a few years.

Start with the “Your First Component” page at https://react.dev/learn/your-first-component and locate the sentence containing “instead of nesting definitions.” Review the linked “Passing Props to a Component” page for context, then clarify what nesting definitions means and why props are preferred. Done means a React user can understand the phrase and the intended data-passing guidance.