The U.S. Patent and Trademark Office ("USPTO"), which is the federal agency charged with overseeing the registration of trademarks, divides marks into 45 different categories; 34 for products and 11 for services. These categories are known as classes, and are used by the USPTO to help differentiate and keep track of the many thousands of new marks that it registers each year.
Consider that the same word or logo could appropriately qualify as a different trademark in different classes. "Fresher" could be a trademark for the Medical Products class, and also for the Food and Drink class. "Dove" is a well-known shampoo and soap, but "Dove" is also a popular brand of chocolate. A trademark owner must choose the class (or classes) apply to his or her mark.
A trademark owner generally has two reasons to use the classification system, depending on how they answer the following questions.
It may take some research to determine the appropriate class in which your product or service best fits. For instance, does a belt made of woven cord belong under Class 22, which includes cordage and fibers? As it turns out, the answer is "no," because the cord is made into clothing, which belongs in Class 25.
Similarly, if a mark represents a new type of service or product, it may be difficult to decide how to categorize it. For example, if you are running an Internet-based store-to-home grocery ordering and delivery service, you may wish to register in a variety of classes, including International Classes 29 (meats and processed foods), 35 (advertising and business), 9 (electrical and scientific apparatus), and 39 (transportation and storage).
Because goods or services in the same class are usually considered related or competing, the use of the same or similar marks within the same class has a high potential for customer confusion. It's important to understand that by itself, the fact that two products or services are in the same or different classes does not conclusively establish whether two marks are legally in conflict. Because the international classification system has packed all goods and services into only 45 classes, combining, for example, abrasive cleansers and cosmetics, products within the same class may be marketed in totally different ways so as to avoid customer confusion.
We have included "coordinated classes" with each class entry. The PTO has grouped the various international classifications into what it calls "coordinated classes." The PTO considers these classes "related" for the purpose of trademark searching.