Acquired distinctiveness (also called secondary meaning) is the process by which a mark that is originally descriptive, generic, or otherwise lacking in inherent distinctiveness becomes protectable through long and exclusive use in commerce. The mark acquires distinctiveness when consumers come to associate it with a single commercial source rather than with a general description or category.
In the US, acquired distinctiveness can help descriptive marks to be registered if the applicant can demonstrate that the mark has developed a secondary meaning in the minds of consumers. Evidence includes the length and exclusivity of use, the volume of sales, advertising expenditure, consumer surveys, and media coverage.