In an ongoing legal battle over its App Store trademark, Apple has hit back at Amazon.com, denying Amazon's claim that "App Store" is a generic term.

In papers filed in federal court yesterday, Apple said it "denies that the mark APP STORE is generic and, on that basis, denies that the Amazon Appstore for Android service is an 'app store.'"

Apple also told the court that it does not believe "the words 'app store' together denote a store for apps," or that "the words 'app store' are commonly used among many businesses to describe mobile software download services and further denies that the term 'app store market' is used to describe the market for mobile software download services," according to the documents submitted to the court.

Apple sued Amazon in March after the company launched the Amazon Appstore for Android, saying Amazon using the term could "confuse" customers.

Amazon countered the suit last month, telling a court that "App Store" is too generic, and asked for Apple's suit to be tossed out. To back up those claims, the company cited a quote from Apple CEO Steve Jobs during an Apple earnings call last October, where Jobs refers to similar offerings on Android as "app stores."

Meanwhile, Apple has also encountered opposition from Microsoft in its own attempt to trademark its App Store. Though Apple applied for the trademark in 2008, in January Microsoft told the U.S. Patent and Trademark Office that the term was too generic to merit a trademark, going so far as to bring in linguistic experts to parse the meaning of "app store."