Updated

DES MOINES, Iowa -- An Iowa-based convenience store has asked a federal judge to rule that the word "footlong" is part of the general English language and not the special property of the Subway restaurant chain.

Ankeny-based Casey's General Stores Inc. filed a lawsuit against Subway in U.S. District Court in Des Moines on Friday seeking a declaration that Casey's use of the word "footlong" to describe its 12-inch-long sandwiches doesn't violate any right owned by Subway.

Casey's lawsuit also seeks a declaration that "footlong" is a generic description of a sandwich that measures one foot, and that Subway's attempt to assert trademark rights is "frivolous litigation."

"We maintain the use of "footlong" by itself to describe a sandwich, which is approximately a foot long, is as old as the hills and everybody has that right and has had that right since they've been making foot-long sandwiches," Ed Sease, an attorney for Casey's, said Monday.

The lawsuit was first reported by The Des Moines Register on Monday.

Subway, owned by Doctor's Associate Inc. of Plantation, Fla., has used the phrases "$5 footlong" and "five-dollar footlong" for years at its 34,000 stores.

Casey's describes sandwiches as "footlong" on menu boards at about 180 stores, and intends to roll it out in all of its 1,600 stores in the Midwest, Sease said.

The dispute between Casey's and Subway surfaced when one of Subway's lawyers, Valerie Pochron, wrote to Casey's on Jan. 31, saying Doctor's Associate had applied for the trademark "footlong" for its sandwiches. In the letter, Pochron told Casey's it was on notice to "cease and desist" from using "footlong" and remove all references to it or face legal action.

Pochron did not immediately return a call seeking comment Monday.

Sease said Subway has applied for two different trademarks for "footlong," one referring to sandwiches and another for restaurant services.

The U.S. Patent Office rejected the request for restaurant services, and the sandwich trademark is going through the approval process, he said. Before a final ruling, the Patent Office must give others a chance to oppose it.

Long John Silvers, Taco Bell Corp., Kentucky Fried Chicken, Dairy Queen, Pizza Hut and Domino's opposed the trademark, according to the lawsuit.

In 2009, Subway took action against Pennsylvania-based convenience store Sheetz Inc. seeking a restraining order and a preliminary injunction over the use of "footlong." A federal judge in Virginia denied Subway's request.

Sease said the Virginia case was not a "legal holding" that the word "footlong" is generic, and that Casey's lawsuit could settle the issue.

"We're after a final determination and order at the end of a trial that says it's generic," he said.

Subway had yet to file a response to Casey's lawsuit Monday.