cannula n 1: a small flexible tube inserted into a body cavity for draining off fluid or introducing medication
Cannula \Can"nu*la\, n. [L. cannula a small tube of dim. of canna a reed, tube.] (Surg.) A small tube of metal, wood, or India rubber, used for various purposes, esp. for injecting or withdrawing fluids. It is usually associated with a trocar. [Written also {canula}.] [1913 Webster]