Any phrase, name, word, or graphic logo used by one manufacturer or marketer to distinguish its products from those of all others. A trademark’s main purpose is to assure the genuineness of an article, and it is roughly equivalent to a commercial signature. For a trademark to be eligible for federal protection, it must be distinctive, attached to a product that is actually marketed, and registered with the United States Patent and Trademark Office. 2 The body of law that is concerned with how businesses uniquely differentiate their products.