By Josh Ong

Published: 10:30 PM EST (07:30 PM PST)

Microsoft and several major handset makers, including HTC, Nokia and Sony Ericsson, are now opposing Apple's trademark of the term "App Store" in the European Union for being generic.

Microsoft has lodged a formal application for declaration of invalidity of the "App Store and "Appstore" trademarks with the EU's Community Trade Mark office, the Digital Daily blog reports. The Redmond, Wash., search giant is joined by HTC, Nokia and Sony Ericsson in opposing the trademark in the EU.

"Microsoft and other leading technology companies are seeking to invalidate Apple’s trademark registration for APP STORE and APPSTORE because we believe that they should not have been granted because they both lack distinctiveness,” a Microsoft spokesperson said in a statement. “The undisputed facts establish that ‘app store’ means exactly what it says, a store offering apps, and is generic for the services that the registrations cover.”

Apple filed for the "App Store" trademark in July 2008 within weeks of launching the iPhone App Store. The trademark applies to "retail store services featuring computer software provided via the internet and other computer and electronic communication networks; Retail store services featuring computer software for use on handheld mobile digital electronic devices and other consumer electronics," as well as the "electronic transmission of data via the internet" and "maintenance, repair and updating of computer software."

In January, Microsoft filed an opposition to the mark with the U.S. Patent & Trademark Office, alleging the term is generic and unregisterable. Apple responded by noting that the "Windows" mark is generic.

"Having itself faced a decades-long genericness challenge to its claimed WINDOWS mark, Microsoft should be well aware that the focus in evaluating genericness is on the mark as a whole and requires a fact-intensive assessment of the primary significance of the term to a substantial majority of the relevant public," Apple wrote.

"Yet, Microsoft, missing the forest for the trees, does not base its motion on a comprehensive evaluation of how the relevant public understands the term APP STORE as a whole."

A day before Amazon launched its Amazon Appstore digital application storefront for Android, Apple filed a suit against the company for violating its trademark. Amazon responded by joining Microsoft in opposition to the mark, also claiming that the trademark is a generic term.

Both Apple and Microsoft have employed the use of linguistic experts to argue their claims for and against the trademark. Apple has also sought to defend its trademark from a pornography store on the Android Market.