Which of these words was NOT originally a trademarked brand name that later became a generic term in everyday language?

Brand slogans and product names often introduce new words into our language. These corporate-created neologisms sometimes become so successful they enter everyday vocabulary. This phenomenon, called 'proprietary eponymy,' represents a fascinating intersection of linguistics and marketing where brand terms become generic descriptors. Test your knowledge about famous brand terms that transitioned from trademarked names to common vocabulary!

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Thermos (insulated container)
Escalator (moving staircase)
Dictionary (book of definitions)
Zipper (interlocking fastener)