As the fifth anniversary of the App Store approaches, Apple is commemorating the occasion with wall posters and app giveaways — and a bit of housecleaning in the litigation department. On Tuesday, Apple abandoned the lawsuit it brought against Amazon over the “App Store” trademark. Filed in March of 2011, that suit accused the retailer of trademark infringement and unfair competition, arguing that its Android Appstore would mislead customers. “Consumers of mobile software downloads are likely to be confused as to whether Amazon’s mobile software download service is sponsored or approved by Apple,” Apple alleged. Amazon countered that the term “app store” is generic, and that it’s silly for Apple to claim otherwise, when its own executives use it generically. “Apple presumably does not contend that its past and current CEOs made false statements regarding those other app stores to thousands of investors in earnings calls,” Amazon said.