In the United States, a letter of the alphabet or a combination of two or three letters which may or may not form a word, as well as a number or combination of numbers, may function as a trademark provided that the designation is not descriptive. However, in most countries outside of the United States, such marks may not be protectable, without providing substantial evidence that the mark has acquired distinctiveness through extensive use in the relevant country.

Certain musical groups, in their overexuberance to be distinctive and shocking, fall into the trap of adopting marks that may be objectionable because they are deemed to be offensive. Although specific references are unnecessary, any patron of modern musical groups may be familiar with band names that might be regarded as offensive. Due to the United States Trademark Office’s obligation under the Lanham Act to reject offensive marks, such marks are difficult to register and to protect. Although common law rights in such names may develop, courts may also be disinclined to offer protection even under common law principles. The case is even worse in foreign countries, which tend to have much stricter standards concerning offensive marks. For example, a record label that has as part of its logo two reclining nude figures of the opposite sex has been unregistrable as such in certain Arab countries, where piracy is rampant, thus requiring the record company to modify their logo for such countries.

Difficulties may be encountered when parties adopt seemingly innocuous trademarks that are used in other countries where they take on new significance. Noteworthy examples of such unsuccessful marks in the automotive industry included the Renault FUEGO in Mexico, where the latter word connotes homosexuality; the Daewoo ESPERO in Spain, where the latter word means “I wait”; the Vauxhall NOVA in Spain, where the latter word means “no go”; and the Citroen SAXO in Japan, where the latter word means "turd". An example in the music industry might be NELLY, which in England is a derogatory word for an effeminate man or homosexual.