Catheter

kath′e-tėr, n. a tube to be introduced through the urethra into the bladder to draw off the urine, or for injecting air or fluids into the Eustachian tube.— ns. Cath′eterism ; Cathetom′eter , an instrument for measuring small differences of level of different liquids in tubes; Cath′etus , a straight line falling perpendicularly on another straight line or surface. [Gr. kathetos , perpendicular, kathetēr , from kathienai , to send down.]