Generally speaking, a trademark is a word, symbol, phrase, or device that uniquely identifies a particular company or individual. There are many types of bottles used to contain soft drinks, for example, but only one with the distinctive logo and design of Coca-Cola®. Each element of a Coca-Cola® bottle — the shape, red imprint, and name — could be considered a trademark of the Coca-Cola company. Because all of these elements have been legally registered with the United States Patent and Trademark Office (USPTO), no other soft drink company can create a similar bottle.
This same philosophy holds true with distinctive slogans or brand names. A photocopying machine is not a trademark, but Xerox® is. Any product bearing the name Xerox® implies the same level of quality as the original product. Sometimes, a brand name becomes so popular that it replaces the generic description of the product. Consumers shop for Q-Tips® instead of cotton swabs, for instance, even though the name is a registered trademark of the Johnson and Johnson company. Other trademarks that have become universal include Jacuzzi®, Band-Aid®, and Crayola®.
A trademark should be registered with agencies such as the United States Patent and Trade Office for maximum legal protection. The law works much like copyright law in the sense of first rights. Once a company or individual successfully registers their word or phrase, which can be done online at the official USPTO website, a circled "R" or the abbreviation "Reg. TM" can be legally printed on the product or slogan. There is no "pending" condition like there is for applications for patents, which may take years to process through the USPTO.
Sometimes, the criteria for registration can be challenging to understand. Companies and individuals cannot simply register ownership of common words or phrases, but they can turn a distinctive combination of words into a trademark. The Nike® shoe company has a legal right to the phrase "Just Do It" because the words have become an identifiable slogan. The swoosh, as simple as it may appear, is also a registered trademark. This doesn't mean, however, that another company can't use a stylized check mark, but must not be designed so that it could be readily confused with the swoosh logo owned by Nike®.
Companies and individuals who have registered a trademark will usually pursue many legal avenues to protect it. Courts must decide if the unauthorized use of a trademarked slogan or product by others has caused actual damage in the marketplace. A local restaurant featuring fried chicken, for example, cannot use the image of an elderly man in a white suit as its official logo. This would create confusion with the registered trademark of Colonel Sanders owned by KFC™. It would be legal for the local restaurant to say "If Mr. Sanders ate here, he'd be a General," however. The law does not protect individual words, just the entire phrase or symbol.