A trade name or mark that is descriptive of the products or services being sold and which cannot be registered for a trademark protection unless it acquires a distinct meaning over the course of time. Used in trademark law, this a word mark which describes the product or service and is not unique. For example, QuickGas as a mark is descriptive of the products sold at a common gas station. Typically registration of such marks are placed on the supplemental register, rather than Principal Trademark Register, which does not provide as much protection. If a descriptive mark has been in use for five years without protest, it may be moved to the Principal Register since it becomes a well known mark.