A more thorough explanation:

In law, dilution refers to the use of a trademark or trade name in commerce that is similar enough to a famous mark that it confuses or diminishes the public's perception of the famous mark. This can happen in two ways:

• Dilution by blurring: This occurs when the distinctiveness of a famous mark is impaired by association with another similar mark or trade name.
• Dilution by tarnishment: This occurs when the reputation of a famous mark is harmed through association with another similar mark or trade name.

For example, if an appliance company puts white apple logos on their appliances, it could dilute the trademark of Apple by confusing consumers as to whether Apple began creating completely new items. This would be an example of dilution by blurring.

Many countries around the world provide dilution protection in some form as a part of trademark law. In the United States, the Federal Trademark Dilution Act (FTDA) creates a federal cause of action to protect famous marks from unauthorized use and to prevent dilution of the distinctive quality of such marks.

The owner of a famous mark is entitled to an injunction against another person who uses a mark or trade name in commerce that is likely to cause dilution of the famous mark regardless of the presence or absence of actual or likely confusion, of competition, or of actual economic injury.

To establish a claim of dilution, the mark must have become famous before use of the allegedly diluting mark or trade name began.

For example, if a new company started using a logo that was similar to the Nike swoosh, Nike could claim dilution because their mark was famous before the new company started using a similar logo.

The factors to be considered in determining whether a mark or trade name is likely to cause dilution by blurring include:

• The degree of similarity between the mark or trade name and the famous mark
• The degree of the famous mark's inherent or acquired distinctiveness
• The extent to which the owner of the famous mark is engaged in substantially exclusive use of the mark
• The degree of recognition of the famous mark
• Whether the user of the mark or trade name intended to create an association with the famous mark
• Any actual association between the mark or trade name and the famous mark

Certain uses of famous marks, such as fair use, are not actionable as dilution. Fair use includes use of the mark other than as a designation of source for the goods or services in connection with advertising or promotions that permit consumers to compare goods or services, and identifying and parodying, criticizing, or commenting on the owner of the mark or the goods or services connected with the mark.

For example, if a comedian made a joke about a famous brand of soda, they could use the brand name in their joke without being accused of dilution because it falls under fair use.