A more thorough explanation:

A parent application is a type of patent application. It refers to the original application that was filed for a patent. If additional applications are filed based on the original application, they are called "child applications."

For example, if a company files a patent application for a new type of phone, that would be the parent application. If they later file another application for a new feature to be added to the phone, that would be a child application.

Parent applications are important because they establish the priority date for the invention. This means that if someone else tries to file a similar patent application after the parent application has been filed, the parent application will have priority.