TRADEMARKS, IN GENERAL
A trademark is any word, design, configuration, slogan, etc. which functions to distinguish a product. Most trademarks are word marks (like KODAK for film or IVORY for soap). The second most common type of trademarks are design marks, which might be representational (like the Rock of Gibraltar) or an abstract design or symbol (like an asterisk or a triangle). Design marks include letters or initials, like GE, GM, RCA, etc.
Trademark rights arise from either actual use of the mark or by filing an application to register a mark in the Patent and Trademark Office stating that the applicant has a bona fide intention to use the mark in interstate commerce. A service mark is the same as a trademark except that it identifies and distinguishes a service rather than a product.