In addition to a label, logo, or other identifying symbol, a product may come to be known by its distinctive packaging -- for example, the blue and yellow packaging of the Advil pain reliever box. Similarly, a service may become known by its distinctive decor or shape -- for example, the yellow arches that symbolize McDonald's franchises.
Collectively, these types of identifying features are commonly termed "trade dress." Because trade dress often serves the same function as a trademark or service mark -- the identification of goods and services in the marketplace -- trade dress can be protected under the federal trademark laws and, in some cases, registered as a trademark or service mark with the U.S. Patent and Trademark Office (USPTO).
Consumers often make their purchasing choices on the basis of recognizable trademarks. For this reason, the main thrust of trademark law is to make sure that trademarks don't overlap in a manner that causes customers to become confused about the source of a product.
If two similar trademarks are being used by companies that provide different products or services, there may not be a trademark conflict. This is especially true if the two businesses serve only local markets and are hundreds of miles apart.
However, in the case of trademarks that have become famous -- for example, McDonald's -- the courts are willing to grant broader protection and prohibit almost all use of the trademark (or anything close to it) by anyone other than the famous mark's owner.
For more information on how to prevent others from using a trademark, see Enforcing Your Trademark Rights.
A trademark is a distinctive word, phrase, logo, domain name, graphic symbol, slogan, or other device that is used to identify the source of a product and to distinguish a manufacturer's or merchant's products from others. Some examples are Nike for sports apparel, Gatorade for beverages, and Microsoft for software.
A service mark does the same thing as a trademark, but while trademarks promote products, service marks promote services and events. Some familiar service marks are: Google (online searching services), Netflix (video rental service), and the FedEx logo (delivery services).
In order to be eligible for trademark protection, a word or phrase must be "distinctive" -- unique enough to help customers recognize a particular product in the marketplace -- rather than generic, like "The Coffee House." To determine whether a potential business name or product name is trademarkable, and how to trademark it, see Trademark: Legal Care for Your Business & Product Name, by Attorneys Stephen Elias and Richard Stim (Nolo), or the Qualifying for Trademark Protection FAQ.