King-Seeley Thermos Co. v. Aladdin Industries, Inc.
United States Court of Appeals for the Second Circuit
321 F.2d 577 (1963)
Thermos Co. (plaintiff) advertised "Thermos" for its vacuum-insulated bottles starting in 1907 without initially treating it as a source identifier, and by the time it launched a 1923 campaign to reclaim the term as a trademark, public understanding had already drifted toward treating "thermos" as the generic name for any vacuum-insulated bottle. Aladdin (defendant) began selling its own vacuum-insulated bottles marketed as thermos bottles, and Thermos Co. sued for infringement; the district court found the term had become generic and ruled for Aladdin.
Whether a trademark term becomes generic if the public primarily understands the term as describing a type or category of goods and not as an identifier of the source of goods.