What Can be Trademarked
Words and phrases are generally divided into categories. Fanciful words or phrases are made-up words that do not have any meaning outside of the context of the business itself. For example, terms like Pinterest or Hulu. Arbitrary marks use existing words in a way different from its common definition, such as Apple computers or a Tweet. Fanciful or arbitrary words or phrases are relatively easy to trademark. Descriptive names that rely on surnames or geographic locations, such as Smith Consulting or New York Times, can only be trademarked when the business can demonstrate that the terms used have a secondary meaning.
General terms that describe a product or service the business provides cannot be trademarked. So a dairy cannot trademark the term "milk" and an email hosting company cannot trademark "email." These types of trademarks are prohibited because they would give the business that holds the trademark an unfair advantage over competitors.
Sometimes, a trademarked term can become so tied to the identity of a particular kind of product that it becomes generic -- which can lead to the loss of a trademark. Examples of product terms that were trademarked and lost that status include zipper and aspirin. This often happens because the holder of the trademark does not properly monitor and police the use of the term in public. When the term in question becomes commonly used to refer to a product regardless of its manufacturer and a competitor uses the term to advertise its own services, the trademark holder may sue in federal court. If the judge determines the term in question now describes a class of products or services and not just the good or service provided by the trademark holder, she will now deem the term to be “generic” and strip the trademark.
To prevent a trademarked term from becoming generic, a business should use the term in question appropriately in its advertising materials. This means to emphasize the term as a brand. One way to do this is to use the term as an adjective or verb. So instead of making a “Xerox” or using “Windex,” a business should use a Xerox copier or a Windex window cleaner. In advertising, the company should state: "Use your Windex window cleaner to make your windows sparkly clean" instead of "Use Windex to make your windows sparkly clean." The trademarked phrase should also always be presented in the same, distinctive manner and include a trademark notice signifying it has legal protection. Members of the general public should not refer to copiers not made by the Xerox Corporation as "Xerox" machines but as copy machines, because only copy machines made by Xerox are Xerox copiers; copiers made by other manufacturers are copiers, or hypothetically, a "Jones" copier, if the copy machine is manufactured by the Jones Corporation.