GigaOM reports that Apple is “doubling down” efforts to defend its use of the term “app store,” updating its complaint against Amazon concerning the retailer’s use of the name Appstore for its own efforts.

Apparently, updated court filings show that the iPhone maker has called for an Amazon executive to testify on Amazon’s decision to drop the term “for Android” when discussing the store, a decision it said is “highly relevant” to its case.

The news comes shortly after a Wall Street Journal report which said: “Apple is paying close attention to Amazon’s app store, according to developers, who said Apple executives have told them they think Amazon’s controlled, iTunes-like approach makes it more competitive than other app stores, including one operated by Google”.

While Google has widely been criticised for weak monetisation options for Google Play – which it has been working to rectify – Amazon is in a similar position to Apple. Through its core retail business it already has a large customer base with credit card details stored in its system, in a similar way that Apple has with its iTunes customer base and payment mechanisms.

Apple has been claiming ownership of the term “app store” for some time, with various legal disputes open and mixed results reported.

In addition to Amazon, companies involved in disputes include Microsoft and GetJar. The defence has generally been that the term “app store” is generic, and therefore cannot be protected by a trademark.