A trademark or trade mark, represented by the symbols ™ and ®, or mark is a distinctive sign or indicator used by an individual, business organization or other legal entity to identify uniquely the source of its products and/or services to consumers, and to distinguish its products or services from those of other entities. A trademark is a type of intellectual property, and typically a name, word, phrase, logo, symbol, design, image, or a combination of these elements. There is also a range of non-conventional trademarks comprising marks which do not fall into these standard categories.

The owner of a registered trademark may commence legal proceedings for trademark infringement to prevent unauthorized use of that trademark. However, registration is not required. The owner of a common law trademark may also file suit, but an unregistered mark may be protectable only within the geographical area within which it has been used or in geographical areas into which it may be reasonably expected to expand.

The term trademark is also used informally to refer to any distinguishing attribute by which an individual is readily identified, such as the well known characteristics of celebrities. When a trademark is used in relation to services rather than products, it may sometimes be called a service mark, particularly in the United States.

Fundamental concepts

The essential function of a trademark is to exclusively identify the commercial source or origin of products or services, such that a trademark, properly called, indicates source or serves as a badge of origin. The use of a trademark in this way is known as trademark use. Certain exclusive rights attach to a registered mark, which can be enforced by way of an action for trademark infringement, while unregistered trademark rights may be enforced pursuant to the common law tort of passing off.

It should be noted that trademark rights generally arise out of the use and/or to maintain exclusive rights over that sign in relation to certain products or services, assuming there are no other trademark objections.

In order to register trademarks the different goods and services have been classified by the International (Nice) Classification of Goods and Services into 45 Trademark Classes (from 1 to 34 includes goods, and from 35 to 45 services). The idea of this system is to specify and limit the extension of the property right (Intellectual Property), by determining which goods or services are covered by the mark, and at the same time unify the classification system in countries around the World.

Oldest trademarks

Zildjian, the cymbal and gong company, owns the oldest continuously used U.S. trademark -- it should be noted, however, that the first two hundred years of the use of the Zildjian trademark were in Turkey as the family moved to the United States. Venetian glass blowers are thought of as using the longest continuously used trademarks. Wieliczka, a salt mine in Poland, is reported to be the source of the oldest known trademark (circa 1241 A.D.) -- even though this trademark is really appellation of origin. Finally, in trademark treatises, it is usually reported that blacksmiths who made swords in the Roman Empire are thought of as being the first users of trademarks. Other notable trademarks that have been used for a long time include Löwenbräu, which claims use since 1383, and Stella Artois, which claims use since 1366.