Fistula
a shepherd's pipe; a waterpipe. In zoölogy, the intermediate subquadrangular pipe, in insects, formed by the union of the two branches of the anthia which conveys the nectar to the pharynx.
In surgery, a long and sinuous ulcer, having a narrow opening, sometimes In surgery, a long and sinuous ulcer, leading to a larger cavity, and which has no disposition to heal.