A more thorough explanation:

The reverse-confusion doctrine is a rule in intellectual property law that states it is unfair competition if a defendant's use of a title that is confusingly similar to the one used by the plaintiff leads the public to believe that the plaintiff's work is the same as the defendant's, or that it is derived from or associated in some manner with the defendant.

For example, if a small company named "ABC" creates a product with a unique name and a large company named "XYZ" creates a similar product with a name that is very similar to "ABC's" product, the public may believe that "ABC's" product is actually made by "XYZ." This confusion can harm "ABC's" reputation and sales, even though "XYZ" did not intend to copy "ABC's" product.

The reverse-confusion doctrine is different from the conventional passing-off form of unfair competition, where similarity of titles leads the public to believe that the defendant's work is the same as the plaintiff's work or is in some manner derived from the plaintiff. In reverse confusion, the unfair competition results from the confusion created about the origin of the plaintiff's work.