(Fast Company) -- Amazon just revealed its own specially curated version of the Android Marketplace, but has chosen to label it the "Appstore."

Apple, in turn, has now sued Android for trademark violation. The move is a not-so-subtle shot across Amazon's bows.

The suit was filed last week, but has emerged at more or less the same time as Amazon's official unveiling Tuesday of its Android Appstore -- Amazon's version of the free-for-all Google Android Marketplace that, on launch, contains 3,800 apps. It will operate under similar constraints, controls and profit sharing with developers as Apple's version, in the hopes that it will be distinguished from other Android app markets by being "safer" and containing higher quality apps.

But it's the name Amazon's chosen (the Amazon Appstore) that's got Apple rattled. Apple filed a trademark protection over the phrase "App Store" after the release of the iPhone 3G, making what an independent observer may deem a sensible business move -- especially since the App Store is now earning Apple a slight profit, and its archive of apps for iPhone and iPad (and now the Mac too) is an incredibly potent advertising lever.

As a result, the computer giant is now suing to prevent Amazon from using the phrase "Appstore" in any way, including marketing, and is also seeking damages. The accusation is that it's a direct trademark infringement that may "confuse and mislead customers" according to an Apple spokesperson, which is the kind of half-true legal phrase often trotted out in cases like this.

The App Store label is a big bone of contention to many folk at the moment. Back in January, Microsoft postured against Apple's trademark, and has asked the USPTO to void Apple's trademark request on the grounds that the phrase "'app store'" is generic for retail store services featuring apps and unregistrable for ancillary services such as searching for and downloading apps from such stores."

Microsoft was moving to protect its plans for Windows Phone 7 app store sales, and seemed ignorant of the irony in its request--as you may recall, MS's best-selling product is dubbed "Windows," which would definitely seem an arbitrary label and has a very precisely-defined generic use in computing environments that long predates MS's use of it.

But what's Apple really trying to do here? One may suspect that Apple is actually mostly peeved that Amazon is trying to leverage off Apple's own successful brand to push sales of a rival smartphone and tablet PC platform -- Android.

The two companies have a complex friend-and-foe relationship, and Amazon's Kindle e-book reader app is prominent in the iPad (and iPhone) App Stores, while its Kindle e-reader device is almost pitched as a direct competitor to the iPad.

The move to defend Apple's trademark indicates that Apple will act to aggressively protect its App Store ecosystem from challengers, which may include any plans Amazon has to expand its Google Android efforts.

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