A more thorough explanation:

Definition: Acquired distinctiveness refers to the quality of a trademarked word, symbol, or device that identifies the goods of a particular merchant and distinguishes them from the goods of others.

For example, the Nike "swoosh" logo is a trademarked symbol that identifies Nike's products and distinguishes them from other athletic brands. Over time, through extensive use and marketing, the Nike swoosh has acquired distinctiveness, meaning that consumers associate it specifically with Nike and their products.

Acquired distinctiveness is important in trademark law because it allows a trademark owner to protect their brand from infringement by others who may try to use a similar mark or logo. By establishing acquired distinctiveness, a trademark owner can demonstrate that their mark has become a valuable asset and deserves legal protection.