A divisional patent application, also called divisional application or simply divisional, is a type of patent application that contains subject-matter from a previously filed application, the previously filed application being its parent application. While a divisional application is filed later than the parent application, it retains its parent's filing date, and will generally claim the same priority. Divisional applications are generally used in cases where the parent application may lack unity of invention; that is, the parent application describes more than one invention and the applicant is required to split the parent into one or more divisional applications each claiming only a single invention. The ability to file divisional applications in cases of lack of unity of invention is required by Article 4G of the Paris Convention.