Apple has set its sights on the Kindle Fire as part of the company's trademark lawsuit against Amazon. In an amended complaint filed this week, Apple argued that Amazon began altering its own "Appstore" marketing when it introduced the Kindle Fire in September, and Apple sees the move as an attempt to conflate consumer expectations between Apple's App Store and Amazon's.

When Amazon first introduced its Appstore for Android earlier this year, Apple was not pleased. The company immediately filed a lawsuit against Amazon, arguing that Amazon was illegally using Apple's trademarked term "App Store" to market its own products. But things have not gone as smoothly as Apple would have liked; US District Judge Phyllis Hamilton denied Apple its request for a preliminary injunction because she felt Apple hadn't yet shown sufficient evidence that its own trademark had been diluted by Amazon.

In its amended complaint, Apple now says that Amazon is trying to confuse customers further by dropping the "for Android" part of "Amazon Appstore for Android." This began after Amazon started advertising the Kindle Fire, the company's tablet-like e-reader based on Android that some consider a low-budget competitor to the iPad. But it's not the Kindle Fire that's being targeted now by Apple—rather, Apple believes Amazon is using the Kindle Fire to aid the branding transition so that Amazon's Appstore seems even more similar to Apple's App Store.

"Amazon promoted the Fire’s ability to use Amazon’s mobile software download service but omitted the 'for Android' phrase when using the APPSTORE mark," Apple wrote in its amended complaint. "Amazon's use is also likely to lessen the goodwill associated with Apple's APP STORE service and Apple products designed to utilize Apple's APP STORE service by associating Apple's APP STORE service with the inferior qualities of Amazon's service."

Amazon has long maintained that the term "app store" is too generic to be trademarked—a position also supported by Microsoft. Both companies have argued that "app store" is so widely used in the industry that both media and customers are aware of its generic nature, and Amazon even used a quote from late Apple CEO Steve Jobs to defend its case. Amazon's removal of "for Android" in its own marketing materials has clearly irritated Apple, however, and it looks like the company is committed to finding out who can use the "app store" term once and for all.