Phlogistic

Part of speech: adjective

Definitions

1. Relating to or characteristic of a fictional substance once believed to cause combustion and fire; pertaining to heat or inflammation as explained by outdated scientific theory; describing something fiery or inflammable according to early chemistry concepts
2. Connected with an obsolete chemical principle involving a substance thought to be released during burning or rusting; associated with heat or the process of inflammation; referring to the historic notion of combustibility before modern oxidation theories
3. Describing attributes linked to a hypothetical element once thought to be responsible for fire and heat generation; concerning inflammation or heat in a medical or chemical sense based on ancient beliefs; characterizing flammability or burning as explained in early scientific understanding

Etymology: Long before it named a discredited chemical theory, the Greek adjective "phlogistos" simply meant "flammable," built from "phlox," the word for "flame." Chemists in the seventeenth and eighteenth centuries borrowed that root when they proposed that combustible substances contained a fire-like principle, which they called phlogiston, released as flame when burned. The theory explained burning as the loss of this substance, and it dominated chemistry until Antoine Lavoisier showed that combustion actually involves the uptake of oxygen. "Phlogistic" is the ordinary English adjective formed by adding "-ic" to "phlogiston," so it means relating to that substance. Its meaning therefore stays tied to a theory that has been abandoned, and the word now appears mainly in discussions of the history of chemistry.

Synonyms: combustible, inflammable, flammable, oxidizable, combustion-related

Antonyms: nonflammable, incombustible, noncombustible, nonoxidizable, fire-resistant