Definition of "phlogiston" noun usually uncountable , plural phlogistons
(chemistry, historical) The hypothetical fiery principle formerly assumed to be a necessary constituent of combustible bodies and to be given up by them in burning . quotations
Quotations […] air was universally reputed to be a simple or elementary body . It was liable , according to the phlogistians , to vitiation , by the addition to it of phlogiston being more or less phlogisticated , according to the degree of its power to support respiration and combustion .
1810, George Wilson, M.D., F.R.D.E., “General Sketch of Cavendish's Scientific Researches and Discoveries”, in The Life of the Honble Henry Cavendish, page 39