Confusing similarity is a legal standard used in the assessment of trademark applications or in cases involving trademark infringement. As such, it is often used to determine whether the resemblance between the marks in question is so close that it could confound consumers.
Several factors set forth by law are considered in order to determine whether the similarity/similarities between two marks meet this standard.
There are several well-known cases in which courts have employed this standard. In one that dates back to 1973, the Trademark Trial and Appeals Board decided not to let DuPont register a specific mark because of the striking similarities between it and another one used by a different company. DuPont appealed.
The court of appeals in that case determined that federal law allowed it to consider approximately 13 different factors to determine whether there was confusing similarity. The criteria included but was not limited to: