In WordPress, you have the ability to designate a certain theme as your parent theme from within a child theme. Doing so will allow you to bring in the features and functionality of the parent theme to your child theme. This is useful in situations where you want or need to upgrade your theme and don’t want to worry about losing any of your custom styling features.
A child theme will inherit the features, functions, and styling of the parent theme. However, if you wish to make changes to the child theme, you can do so without changing the parent theme.
Keep in mind that a parent theme is not necessarily the same thing as a theme framework. A full exploration of the differences between the two is beyond the scope of this article; suffice to say that while all theme frameworks will also be parent themes, it is not true that all parent themes will also be theme frameworks. Simply put, the parent theme classification is more broad than the theme framework classification.
By using a child theme, you can easily modify your theme to choose which features you want to use, without effecting the overall performance of the parent theme. It is a great way to get cherry pick the features you want, without having to rework the entire layout of the theme.