A trademark is a unique symbol or word(s) used to represent a business or its products. Once registered, that same symbol or series of words cannot be used by any other organization, forever, as long as it remains in use and proper paperwork and fees are paid.
Unlike patents, which are granted for a period of 20 years, trademarks never end. Companies do need to apply for them and receive ownership confirmation with the U.S. Patent and Trademark Office in order to claim protection from copycats, however.
Over time, trademarks become synonymous with a company name, so that you don’t even need to see the name to recognize a particular business. Think of the apple shape with the bite taken out that Apple uses as its logo, the swoosh logo that Nike features on all of its products, or the golden arches McDonald’s registered decades ago.
The fact that we so easily associate symbols and words with companies and their brands is one of the biggest advantages of their use. When a customer sees a familiar logo or phrase, they have instant recognition, which can drive preference and, ultimately, sales.