Lawyers for the two firms have been in discussions to resolve the dispute since a judge ordered them to do so in January. Those discussions include a 45-minute phone call on June 14 and an all-day meeting on May 1.
Involved in the talks have been B.J. Watrous, Apple's chief intellectual property attorney, and Andrew DeVore, Amazon's assistant general counsel. Talks between the parties have so far proved unfruitful.
At issue is Amazon's use of the term Appstore, which Apple says is too close its own App Store. Apple filed suit in 2011, asserting that Amazon's term violated Apple's trademark.
Amazon argued that the term had become generic, saying that it only signifies a digital repository for apps and doesn't specifically call Apple to mind. Other companies, including Microsoft, have petitioned the U.S. Patent and Trademark Office to block Apple's attempts to secure a trademark on the term.
With the matter unresolved so far, it appears likely that the conflict will eventually be settled in court. A trial has been set for August 19.