decoction (n.)

late 14c., decoccioun, "liquor in which an animal or vegetable substance has been boiled;" early 15c., "act of boiling in water," from Old French décoction (13c.) or directly from Latin decoctionem (nominative decoctio) "a boiling down," noun of action from past-participle stem of decoquere "to boil down," from de "down" (see de-) + coquere "to cook" (from PIE root *pekw- "to cook, ripen").