Apple's attempts to own the name "App Store" has taken a setback after a US judge ruled that "false advertising" cannot be used as a claim against online retailer Amazon.

Judge Phyllis Hamilton of the US District Court in Oakland, California, said that Apple had not established that Amazon deliberately used the term "Appstore" for its own variant of the Android app marketplace, to confuse users of Apple's own "App Store".

Apple applied to trademark both "App Store" and "Appstore" with the US Trademark Office in 2008 for its iOS app download service. In April last year, it sued Amazon for trademark infringement following the launch of Amazon's Appstore for Android. Apple later amended that claim to include false advertising, the part of which has now been rejected.

"Apple has failed to establish that Amazon made any false statement (express or implied) of fact that actually deceived or had the tendency to deceive a substantial segment of its audience," Hamilton wrote, according to Reuters.

The judge also said that Apple's service only sells apps for the company's iPhone, iPad and other devices, whereas Amazon's store sells apps solely for devices running Google's Android operating system, such as its Kindle Fire.

The remaining part of Apple's trademark infringement claim is set to go to trial in August. Amazon claims the term "App Store" is too generic and therefore cannot be trademarked.

The iPhone maker already owns a trademark on "App Store" and "Appstore" in Europe, where it is being challenged by Microsoft, HTC, Nokia and Sony.

Microsoft has also filed an opposition to Apple's trademark application in the US. Last year both companies hired linguists to serve as experts in their appeal, with Microsoft claiming the words "App Store" were a generic compound noun, simply describing a "store at which apps are offered for sale." Apple's linguist countered that the term "App Store" was a proper noun and deserved to be trademarked, even though the words are generic when separated.