Definition of phlogiston in English:



  • [mass noun] A substance supposed by 18th-century chemists to exist in all combustible bodies, and to be released in combustion.

    • ‘And combustion, as they understood it, happened when phlogiston, a hypothetical earthlike substance characterized mainly by its combustibility, was removed from an object.’
    • ‘For example, sun-centered astronomy replaced earth-centered, oxygen superseded phlogiston, and absolute space gave way to curved space.’
    • ‘In the phlogiston theory, phlogiston is released during combustion, and in the oxygen theory, oxygen is absorbed during combustion.’
    • ‘According to the phlogiston theory, combustible materials contain a substance - phlogiston - that is emitted by the material as it burns.’
    • ‘Biologists used to believe in the inheritance of acquired characteristics, chemists in phlogiston, physicists in absolute (pre-relativity) time.’


Mid 18th century: modern Latin, from Greek phlogizein set on fire, from phlox, phlog- flame, from the base of phlegein to burn.