In Apple Inc.'s latest effort to control its U.S. trademark for the term "App Store," a law firm representing the company sent a cease-and-desist letter to wireless-application store operator GetJar.

According to a letter reviewed by The Wall Street Journal dated June 22, lawyers from New York's Kilpatrick Townsend & Stockton LLP requested that San Mateo, Calif.-based GetJar stop using "App Store" on its website and elsewhere, and refrain from using the term in the future. The lawyers suggested that the company instead use...