“Unity of invention” is an essential facet of a patent application in India . The term denotes a situation where the claims of a complete specification relate to either a “single invention” or can be “a group of inventions linked to form a single inventive concept”. If a patent application claims more than one invention, it may be rejected because it lacks unity of invention. Where an application covers more than one inventive concept, this hurdle can be overcome by filing a divisional patent application. Divisional patent applications are applications which have been divided from the main application, also known as the parent application. A divisional application allows an applicant to divide the inventions from the parent application into a separate application for each inventive concept without losing his priority rights.