Wiktionary
n. (context chemistry English) an obsolete scientific theory of combustion
Wikipedia
The phlogiston theory is a superseded scientific theory that postulated that a fire-like element called phlogiston is contained within combustible bodies and released during combustion. The name comes from the Ancient Greek φλογιστόν phlogistón (burning up), from φλόξ phlóx (flame). It was first stated in 1667 by Johann Joachim Becher, and then put together more formally by Georg Ernst Stahl. The theory attempted to explain burning processes such as combustion and rusting, which are now collectively known as oxidation.
Usage examples of "phlogiston theory".
A thousand years from now, our current views of physics will seem as primitive as the phlogiston theory seems to us today.
The field of psychodynamics had risen above alchemy and Freudian psychology, to about the level of the phlogiston theory, but had yet to birth its Newton or Lavoisier.
I advised him that I understood, diffidently mentioning that I was no stranger to scientific rigor, my own grandfather having published a massive Evidences for the Phlogiston Theory of Heat.