The legal battle between Apple and Amazon.com over rights the phrase “app store” is starting to get more heated, maybe even verging on a little nasty. In its latest court filing, made public yesterday, Apple argues that Amazon’s use of the phrase for its Android “Appstore” will confuse consumers, making them think that Amazon is offering its own storefront for the Apple App Store.

And that’s a problem, Apple argues, because Amazon’s “inferior service” will then damage Apple’s brand in the minds of those consumers.

It’s the latest in a series of arguments over rights to one of the key phrases of the mobile industry. Microsoft is separately battling with Apple over its attempt to register the “app store” phrase as a trademark.

In the Amazon case, Apple wants a preliminary injunction to prevent Amazon from using the phrase. Here’s a taste of their back-and-forth on the topic, which revolves around the fact that Amazon offers some apps that only work on rooted Android devices.

Apple on April, 13: “Android-based software has been subject to highly-publicized viruses and malicious code—including, in one instance, the infection of hundreds of thousands of Android mobile devices with malicious code—which created significant device stability and data security issues Moreover, Amazon is enabling software to be downloaded through its APPSTORE service that bypasses security safeguards, thereby increasing the risks that its customers’ Android devices will be subject to viruses and malware.”

Amazon, June 1: “Apple’s factual assertions regarding the alleged inferiority of Google’s competing Android operating system are incorrect. There is nothing “cheap or shoddy” about Android or Amazon Appstore for Android.”

Apple, June 8: “Amazon mischaracterizes Apple’s tarnishment claim. Apple has not asserted that the Android operating system is inferior. Rather, Apple has asserted that Amazon’s service is inferior and will tarnish Apple’s mark.”

In its latest filing (PDF, 19 pages) Apple also raises the possibility that Amazon could further confuse consumers at some point in the future by offering its own “Appstore” for Apple iOS devices.

Amazon is currently offering software for use on Android devices that have been “rooted”—the Android equivalent of a “jailbroken” Apple device—and there is no reason to believe Amazon would not offer software for “jailbroken” Apple devices. Moreover, Amazon has recently demonstrated its intent to target Apple’s customers by launching a new service that allows customers to download from Amazon software for MAC personal computers manufactured by Apple.

Amazon calls that Mac download service “Mac Software Downloads,” not an app store, which Apple says demonstrates that alternative phrases are actually available and workable.

A hearing on Apple’s motion for preliminary injunction is set for June 22 in federal court in Oakland, Calif.

Like what you're reading? Subscribe to GeekWire's free newsletters to catch every headline

Job Listings on GeekWork

Find more jobs on GeekWork. Employers, post a job here.