(Reuters) - Amazon.com Inc on Friday defeated an appeal by the U.S. Internal Revenue Service in what the online retailer has called a $1.5 billion dispute over its tax treatment of transactions with a Luxembourg subsidiary.In a 3-0 decision, the 9th U.S. Circuit Court of Appeals in Seattle upheld a 2017 ruling by the U.S. Tax Court related to intangible assets that Amazon.com transferred in 2005 and 2006 to the unit, Amazon Europe Holding Technologies SCS. Intangible assets include such items as customer lists, intellectual property and software. The appeals court rejected a broader definition sought by the IRS that...