A trademark is a word, phrase, symbol, design, or a combination of these, that identifies and distinguishes the source of the goods or services of one party from those of others. A service mark is the same as a trademark except that it identifies and distinguishes the source of a service rather than a product. Throughout this chapter the terms trademark and mark are used to refer to both trademarks and service marks. A mark for goods ordinarily appears on a product or on its packaging, whereas a service mark appears in advertising for the service.