flo jI stan
noun
a nonexistent chemical that was once believed to be the cause of combustion and to be released by anything burning.
As we have seen, Priestley, in 1774, had discovered oxygen, or “dephlogisticated air.” Furthermore, he postulated the theory that combustion was not due to any such illusive thing as “phlogiston,” since this did not exist, and it seemed to him that the phenomena of combustion heretofore attributed to phlogiston could be explained by the action of the new element oxygen and heat. Edward Huntington Williams – A History of Science — Volume 4