sued by Apple sued by Apple is being sued by Apple Inc over the use of the phrase “App store".

The company is accusing of trademark infringement and filed a complaint last Friday [18th March] in the federal court for the Northern District of California, USA, according to the Wall Street Journal.

Apple Inc has called on the court to impose an injunction preventing Amazon from using the phrase, and award unspecified damages on top.

Apple registered for a trademark on the term "App Store" on 17th July 2008, and uses the name to refer to its applications store for software that users can download to their iPhones, iPod touches or iPads.

In its complaint, Apple said: "Consumers of mobile software downloads are likely to be confused as to whether Amazon's mobile software download service is sponsored or approved by Apple."

However, the online retailer uses the word "Appstore," with no space and a lower case 's'.

Amazon is accused of beginning to use the phrase to refer to its mobile-software download service in around January this year.

"We've asked Amazon not to copy the App Store name because it will confuse and mislead customers," a spokeswoman for Apple told the WSJ. Amazon said it did not want to comment on pending litigation.

Although Apple's trademark was approved by authorities, it is also being challenged by Microsoft Corp and is currently subject to proceedings before an appeals board of the US Patent and Trademark Office, Apple said in its filing.

Meanwhile, Microsoft is suing Barnes & Noble, having accused the US bookseller of infringing its patents with its Nook e-book reader device. The technology company is also taking electronic manufacturers Inventec and Foxconn International to court, according to the BBC. Horacio Gutierrez, deputy general counsel of Microsoft's intellectual property and licensing, said: "The Android platform infringes a number of Microsoft's patents, and companies manufacturing and shipping Android devices must respect our intellectual property rights."