What constitutes trademark infringement? In other words, if a senior trademark user goes to court and sues another party for trademark infringement, what does the senior party need to prove? This is a complicated issue, but in general, the senior party would need to prove that there use of the allegedly infringing trademark is likely to cause confusion in the market place – so called “likelihood of confusion.” More specifically, the plaintiff would have to show that a significant portion of the relevant consuming public is likely to be confused by the use of the allegedly infringing mark by the defendant. Also worth noting is that likelihood of confusion is the same test that a trademark examiner at the United States Patent and Trademark Office will employ in determining whether a mark barred from registration because of previously registered mark.

How does one prove that there is a likelihood of confusion? The pivotal case on this point is the so-called du Pont case which lays out the factors that the court may consider in a consideration of likelihood of confusion. Among these du Pont factors are:

1. The similarity between the marks. The closer the marks are to each other, the more likely the court will find that there is a likelihood of confusion. Conversely, the more different are the marks, the less likely. It is worth noting that there is no requirement that the marks be identical in order to find infringement by the later adopted mark.

2. The similarity between the products or services sold under the trademark. Obviously, the more closely related the goods/services, the more likely the court will find infringement. The less closely related, the less likely a finding of infringement.

3. The strength of the senior mark. If the senior mark is strong, there is a greater chance that the court will find that there is a likelihood of confusion, and hence infringement. Generally, stronger marks are those that have been used for longer periods of time, have been more extensively used and advertised, and are inherently distinctive (i.e. not descriptive or generic.)

4. Actual confusion in the marketplace. Although there is no requirement to prove actual confusion in order to prove infringement, actual confusion is a factor which may be considered by the court.

5. The likelihood that the senior party will bridge the gap to selling products or services sold by the alleged infringer.

One can lose rights to a trademark if a mark that was once distinctive becomes the common generic name for a product or service. This may occur when a trademark owner does not properly police the use of his or her mark. In one example, the word “escalator” was once a trademark for a brand of moving stairs, but because of improper policing of the mark it has become generic. The name of a product or service should always be capitalized. It should always be used in conjunction with the common generic name of the goods or service as in “Ford motor car” or “XYZ brand of toilet tissue”. Never use a trademark as a verb; it is improper to “Xerox a document” – instead, one photocopies a document using a Xerox brand copy machine.

Under trademark law, a mark must be distinctive (i.e. capable of distinguishing the product or service from others.) Thus, trademarks are classified according to their level of distinctiveness and are afforded protection according to their classification.

• Arbitrary or fanciful marks. The most distinctive marks are those which are arbitrary or fanciful. Arbitrary marks are those which have no relation to the goods (e.g. Apple for computers) and fanciful marks are coined or invented names (e.g. Kodak film). As long as they are not confusingly similar to other marks, arbitrary or fanciful marks are afforded the highest level of protection.
• Generic marks. On the opposite end of the spectrum of distinctiveness lie generic marks – the common name for the product or service. Generic marks are incapable of protection under trademark law because others need to use the common name to compete effective. Thus, one cannot claim trademark rights in the word ‘desk’ to identify the supplier of a desk.
• Descriptive marks. Between arbitrary/fanciful marks on one end of the distinctiveness spectrum and generic marks on the other end lie descriptive marks. These are marks which describe an attribute, function or use, characteristic, purpose or quality of the goods or services. Descriptive marks are only eligible for trademark protection if they acquire secondary meaning (consumer recognition of the term as a trademark.)