What is a child theme?
A WordPress child theme acts as an intermediary between the parent theme and the design and layout of the website. If a file exists in the child theme which the parent theme attempts to load, the child theme’s version of said file will be loaded in its place.
In contrast to a child theme, the parent theme is the primary theme which contains the necessary files for the theme to function. A child theme will not function properly without an associated parent theme. In some instances a parent theme has not been developed using functions which are intended to load child-theme files in lieu of their parent theme counterparts. In this instance the functionality of the theme will need to be modified in order to load the child theme’s files.