phlegm

1. (historical) One of the four humors making up the body in ancient and mediaeval medicine; said to be cold and moist, and often identified with mucus.Examples: "Each person's unique mixture of these substances determines his temperament: a predominance of blood gives a sanguine temperament; a predominance of phlegm makes one phlegmatic; yellow bile, bilious (or choleric); and black bile, melancholic."historicaluncountableusually

2. (historical, chemistry, alchemy) A watery distillation, especially one obtained from plant matter; an aqueous solution.Examples: "The attempts made to analyse vegetable substances previous to 1720, merely produced their resolution into the supposed elements of the chemists of those days, namely, salts, Earths, phlegm, and sulphur."historicaluncountableusually