NEW YORK (CNN/Money) - Nissan North America Inc. is taking Audi of America Inc. to court over Audi's planned use of a letter of the alphabet that Nissan says is all their own, according to a report Friday. And no, it's not the "Z."

The letter in question is "Q," which Nissan has used on its luxury brand Infinity since 1989 and now Audi plans on using for a line of SUVs, according to an article in the Detroit Free Press.

A patent lawyer contacted by the Free Press said Nissan will have to prove that consumers identify the letter "Q" with its brand and that Audi's use of the letter would cause confusion.

Audi, for its part, will have to show that with the alphabet soup of letters and numbers automakers now use to label their products, consumers rely on much more than one letter to distinguish between a Lincoln LS sedan and a Lexus LS sedan, or a Mercedes ML350 and an Infinity M35, according to the article.

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