Webster's Revised Unabridged Dictionary · 1913

Decoction

Decoction , noun

[French décoction, Latin decoctio.]

1.
The act or process of boiling anything in a watery fluid to extract its virtues.
In decoction... it either purgeth at the top or settleth at the bottom. — Bacon
2.
An extract got from a body by boiling it in water.
If the plant be boiled in water, the strained liquor is called the decoction of the plant. — Arbuthnot
In pharmacy decoction is opposed to infusion, where there is merely steeping. — Latham