Apple has not been shy about going after competitors in court in recent years, and those battles have not been limited to the giant patent lawsuits with Samsung that have garnered worldwide attention. In a federal trademark lawsuit set in Oakland, the company sued Amazon over its use of the phrase "App Store for Amazon," saying it infringes on the trademark for Apple's App Store.

Amazon responded in court papers, arguing that the words "app" and "store" are both generic phrases that can't be trademarked.

Now, after more than two years of litigation, Apple has dropped its case. There was no settlement; Apple just walked away before a trial. It had to give Amazon a "covenant not to sue" over the issue, or else Amazon would have continued with its counterclaims seeking to knock out Apple's trademark.

"This was a decision by Apple to unilaterally abandon the case and leave Amazon free to use 'appstore,'" Martin Glick, a lawyer for Amazon, told Reuters.

Apple tried to put the best face possible on a lawsuit that it pursued for two years and then gave up on.

"We no longer see a need to pursue our case," Apple spokeswoman Kristin Huguet said. "With more than 900,000 apps and 50 billion downloads, customers know where they can purchase their favorite apps."

Of course, litigation is unpredictable, and trademark cases rest on consumer perceptions, which can be especially open to interpretation (not to mention measured with pseudo-scientific surveys). But this case had already progressed to a point where Apple was likely throwing good money after bad. The judge tossed out Apple's false advertising claims in January, and in a hearing last year she showed deep skepticism that there was any consumer confusion between Apple's App Store and Amazon's Appstore for Android.

In Apple's filings last year, it had plead that it was a "pioneering brand" and had played a "unique role in educating consumers about the product market."