water in which a crude vegetable drug has been boiled and which therefore contains the constituents or principles of the substance soluble in boiling water.
Origin: 1350–1400;Middle Englishdecoccioun < Old Frenchdecoction < Late Latindēcoctiōn- (stem of dēcoctiō) a boiling down, equivalent to dēcoct(us), past participle of dēcoquere (dē-de- + coc-, for coquere to cook + -tus past participle suffix) + -iōn--ion