Confusing similarity

Confusingly similar is a term in trade mark law to describe a potential infringement of a protected trade mark where the infringing mark is not identical to the protected trade mark but shares elements of spelling or style that would lead a reasonable observer to believe the trade marks were related.

For example, in the computer industry, the trade mark "Microsoft(TM)" has become so well known that either a competitor or a company in the industry may want to use the term "Micro" in its name. As neither "Micro" or "Soft" are independently protected terms (as they are not contrived names like "Exxon(TM)", Microsoft would have to prove that such products could be confused with its own products in order to proceed. As such, a competing trade mark such as "Microsafe" or "Micro Software", although clearly not identical, could be potentially infringing uses.

In addition, the style of a trade mark, such as a logo or font, can become relevant. For example, Microsoft products are distinguished in the marketplace by a consistent font. Competitors may not use the same font on their product, particularly when using a name which would not be confusingly similar except for the use of the font. For example, a brand called "Microsystems" would most likely not be confused with Microsoft. However if Microsystems used the same font as Microsoft, it would be confusingly similar. Some styles, like the script used on Coca-Cola(TM) products, are so well known that even a completely different name in a similar script could be held to be confusingly similar.

Cases of this type can be proven by using surveys which show that members of the public who are likely to use the services or goods protected by the trade mark have been confused by it. However, courts can also take judicial notice that an infringing mark is confusingly similar if it is obvious to even a casual observer.