DES MOINES, Iowa - Casey??s General Stores has filed a lawsuit against Subway over use of the word "footlong," the Des Moines Register reports. At the center of the dispute is whether the term "footlong" belongs to the sandwich chain or can be used to label any 12-inch sandwich.

While Subway has built numerous ads promoting its footlong subs, Casey??s wants to be able to use the term in its own marketing campaigns for 12-inch sandwiches now offered at its 180 locations. Late last month, Casey??s received a letter from Subway??s attorneys threatening a lawsuit if the convenience store chain persisted in using the word "footlong." Casey??s preempted with its own suit in U.S. District Court.

Casey??s lawsuit requests a jury trial, a ruling that the word "footlong" does not violate Subway trademarks, and unspecified damages because of the sandwich restaurant??s "frivolous" claims. "Casey??s has and will continue to use 'footlong?? to describe a sandwich," wrote the company??s attorney in the petition.

Subway has yet to obtain a trademark for "footlong" by the U.S. Patent and Trademark Office. Restaurants opposed to the trademark application include KFC, Pizza Hut and Taco Bell, among others. Subway has not responded to Casey??s lawsuit as of press time.

The case has implications to numerous restaurants across the country. For example, last year, Hardee??s tested a sandwich featuring three beef patties on a 12-inch bun.