D defs.my
Entry 1 sense Webster, 1913

Phlogiston

/(flō̇*jĭs"tŏn; 277)/ · Phlo·gis·ton · IPA /flə(ʊ)ˈd͡ʒɪstɒn/
01 n. The former hypothetical principle of fire, or inflammability, regarded by Stahl as a chemical element; it is now known to be nonexistent.
  1. 1.
    The former hypothetical principle of fire, or inflammability, regarded by Stahl as a chemical element; it is now known to be nonexistent.(Old Chem.)