Kellogg v. National Biscuit
Kellogg Co. v. National Biscuit Co. · 1938 · Supreme Court of the United States
What happened
The Court held that "shredded wheat" had become generic and that the pillow shape was functional, so neither could be monopolised after the underlying patents expired.
The money
No reliable public figure. This dispute matters for the rule it settled rather than for a damages number, and many trademark matters resolve on confidential terms.
What it means for your business
A name that describes the product itself may be unownable, and a name can become generic through success. Choosing an invented word rather than a description of what you sell avoids both problems.