cohobate (KOH-hoh-bait) - v.t., to re-distill (a substance) by pouring it back into the matter remaining in the still.
This is an alchemical term carried over into early chemistry and, especially, pharmacology. It looks like it may even have been introduced by Paracelsus himself (he who gave us bombast from his name) -- and certainly comes from Medieval Latin cohobāre, over which there is some dispute. Some hold the original meaning of the Latin is to give a darker color to (a distilled liquid), and trace it to Arabic qohba, brownish color, while others trace the repeated distillation sense to Arabic ka`aba, to repeat an action. By way of example, from The Gentlewoman's Companion: or, A Guide to the Female Sex:
"Peach-flowers, and of Worm-wood of each a pint and half; let them be digested in a Glass-Vessel three days, then distil them; cohobate this."