From Generic to Fanciful: The Distinctiveness Scale
Trademark strength is measured by distinctiveness, which ranges from generic (no protection) to fanciful (strongest). A generic mark is the common name of the goods or services: 'Elevator' cannot be trademarked for an elevator company; it is what the product is called. Descriptive marks describe the goods, ingredients, or origin: 'Pain Reliever' for a medicine is descriptive and normally unregisterable. Suggestive marks evoke the product's characteristics through imagination: 'Orange Crush' for an orange beverage is suggestive (you must think to connect the mark to the product). Arbitrary marks are real words applied to unrelated goods: 'Apple' for computers is arbitrary (apples and computers are unrelated). Fanciful marks are invented words: 'Xerox' and 'Kleenex' are fanciful. Arbitrary and fanciful marks receive strong protection immediately; descriptive marks need secondary meaning (consumer recognition that the mark identifies a specific source) to be registerable.
Acquisition and Maintenance of Strength
A mark's strength grows with use and investment in consumer recognition. Weak marks are vulnerable to challenges (someone else can register a similar mark in a different field). Strong marks earn the status of 'famous mark,' giving broader protection against dilution (use on dissimilar goods that tarnishes the brand). A mark can be weakened by genericide if the owner fails to police use and the mark becomes synonymous with the product class: 'Escalator' and 'Thermos' lost protection this way (though not entirely). Maintaining protection requires regular use in commerce, renewal filings (every 10 years federally), and policing against infringement and generic drift. 'Google' is now sometimes used generically ('let me google it'), and Google actively polices to prevent loss of the trademark.