A service mark is a word, phrase, or symbol (such as a logo) that is associated with a service, and which distinguishes the service of an organization. It is essentially a trademark that has been applied to a service, and can only apply to a service that is provided to others (not an internal service). For example, a delivery service could create a phrase, such as "faster than the speed of light," and apply it to the company's service as a service mark.
The registration process for a service mark is the same as the process used for a trademark. When a service mark has been federally registered, it is identified with an (R). A common law service mark is accompanied by the superscript SM.