SAN FRANCISCO — The U.S. Court of Appeals for the Ninth Circuit has refused to enforce a so-called “browsewrap” arbitration agreement incorporated into the website of Barnes & Noble Inc. against customers who claim the bookseller reneged on their purchases of discounted computer tablets.

Barnes & Noble did not take adequate steps to assure its customers were aware of an arbitration agreement tucked in the website’s terms of use, a unanimous three-judge panel ruled Monday. The panel affirmed the 2012 decision of the U.S. District Court for the Central District of California and denied Barnes & Noble’s motion to compel arbitration.