10 letters · 16 points in Scrabble
noun a hypothetical substance once believed to be present in all combustible materials and to be released during burning
originFrom New Latin phlogiston, coined by Georg Ernst Stahl in 1702, from Ancient Greek φλογιστόν (phlogistón), neuter of φλογιστός (phlogistós, “burnt up, inflammable”), from φλογίζω (phlogízō, “to set fire to”), from φλόξ (phlóx, “flame”).
Etymology from Wiktionary, CC BY-SA 3.0