Apple is "doubling down" on efforts to drive Amazon away from the term “app store," according to "GigaOm" (http://macte.ch/wZoxo).

In court filings last week, Apple demanded that Amazon provide an executive to testify why the company decided to remove the words "for Android" from some of Amazon’s app store marketing, the article adds. The filing also repeats allegations that Amazon’s use of "Amazon Appstore" with the Kindle Fire tablet was intended to confuse consumers.

Last year Apple sued Amazon, saying the online retailer is using Apple’s “App Store” trademark for a mobile-software developer program. In a complaint filed March 18, 2011, in federal court in northern California, Apple accused Amazon.com of trademark infringement and unfair competition and asked for a judge’s order to prevent the company from using the "App Store" name, as well as for unspecified damages.

Apple registered for a trademark on the term App Store on July 17, 2008. It has been using the name since then to refer to its applications store for iOS devices. Earlier this year it also launched the Mac App Store.

"Amazon has begun improperly using Apple’s App Store mark in connection with Amazon’s mobile-software developer program," Apple said in the complaint. Amazon also plans to use the name with a mobile-software download service, the complaint states.

Amazon began using the App Store designation around the beginning of this year, according to the lawsuit. “Amazon has unlawfully used the App Store mark to solicit software developers throughout the United States," Apple claimed in its suit. In the court filing, Apple said in the court filing that it contacted Amazon three times to demand that it cease using the name and that Amazon hadn’t "provided a substantive response."

Amazon responded in court to Apple's trademark infringement lawsuit over the use of the term "App Store," which Amazon has contended is generic and should be free to use.