one trademark and one application. The principle of single trademark application, also known as the principle of one invention and one application, means that a patent application document can only file a patent application for one invention and creation. That is, a trademark and an application. Trademark is a special legal term. A brand or a part of a brand is called a "trademark" after it is registered by the relevant government departments according to law. Trademarks are protected by law, and registrants have exclusive rights.