What is a WordPress Child theme? Does this child have a parent? Why is it called a Child Theme? The answer is simple.
A WordPress Child Theme is basically a WordPress theme that borrows template files and functionalities from a WordPress parent theme. A parent theme is a the main theme that the child theme relies on. For instance, you can create a theme out of WordPress Twenty Fourteen theme. The new theme created from that theme is called a Child Theme. How is it possible? This happens by mimicking the parent theme or creating a copy of it. Sounds like magic? It better be.
So here is a blog that states everything you need to know about WordPress child themes: http://www.wpexplorer.com/wordpress-child-theme-guide/