Definitions

1. adjective

relating to or denoting a theory that combustion is a chemical reaction in which a substance combines with phlogiston, an hypothetical fire-like element; now often used in a more general sense to describe something as being highly reactive or combustible.

“The phlogistic properties of the new fuel made it highly sought after.”

2. noun

a substance or element that is highly reactive or combustible, especially one that readily ignites or burns.

“The phlogiston in the old-fashioned fireworks caused the explosion.”