A trademark is “a word, symbol or design, or a combination of these, used to distinguish the goods or services of one person or organization from those of others in the marketplace.” There are unregistered trademarks and registered trademarks. As soon as you create and use an original mark, it becomes a form of intellectual property. Trademark registration isn't necessary for legal protection against unauthorized use.
A service mark is a mark that identifies and distinguishes the source of a service.