phlo·​gis·​ton flō-ˈji-stən How to pronounce phlogiston (audio)
: the hypothetical principle of fire regarded formerly as a material substance

Examples of phlogiston in a Sentence

Recent Examples on the Web Lavoisier didn’t think that Priestley was right about phlogiston, prompting a long-running battle. Kat Eschner, Smithsonian, 25 Aug. 2017

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Word History


New Latin, from Greek, neuter of phlogistos inflammable, from phlogizein to set on fire, from phlog-, phlox flame, from phlegein

First Known Use

1733, in the meaning defined above

Time Traveler
The first known use of phlogiston was in 1733

Dictionary Entries Near phlogiston

Cite this Entry

“Phlogiston.” Dictionary, Merriam-Webster, Accessed 6 Dec. 2023.

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