This river is in Brazil, South America. There are thousands of businesses, and hundreds of brandnames in Brazil, which are properly named after it. But this Internet retailer is very USA.
And it really has nothing to do with the river. If they liked the sound of Amaz, they could have selected Amaza, or Amazin, and both could have been developed into a proper unique brand identity. Amazon will never be that.
That’s the shortcoming of geographical terms.
1 Mary W. Sullivan, Brand Extensions: When to Use Them, Graduate School of Business, University of Chicago, 1101 E. 58th Street, Chicago, Illinois 60637
2 Aswath Damodaran , Dealing with Intangibles: Valuing Brand Names, Flexibility and Patents, New York University – Stern School of Business April 7, 2007