Is it ensure, insure, or assure?
1550s, "make return in kind" (especially of an injury), from Old French retort and directly from Latin retortus, past participle of retorquere "turn back, twist back, throw back," from re- "back" (see re-) + torquere "to twist" (see thwart). Applied to exchanges of jest or sarcasm by c.1600, hence "say or utter sharply and aggressively in reply" (1620s). Related: Retorted; retorting.
"act of retorting," c.1600, from retort (v.).
"vessel used in chemistry for distilling or effecting decomposition by the aid of heat," c.1600, from Middle French retorte, from Medieval Latin *retorta "a retort, a vessel with a bent neck," literally "a thing bent or twisted," from past participle stem of Latin retorquere (see retort (v.)).
retort re·tort (rĭ-tôrt', rē'tôrt')
A closed laboratory vessel with an outlet tube, used for distillation, sublimation, or decomposition by heat.
vessel used for distillation of substances that are placed inside and subjected to heat. The simple form of retort, used in some laboratories, is a glass or metal bulb having a long, curved spout through which the distillate may pass to enter a receiving vessel. The design dates back to the cucurbit (flask) used by medieval alchemists.