/kath"i teuhr/ , n. Med.
a flexible or rigid hollow tube employed to drain fluids from body cavities or to distend body passages, esp. one for passing into the bladder through the urethra to draw off urine or into the heart through a leg vein or arm vein for diagnostic examination.
[ 1595-1605; kathetér kind of tube, lit., something sent or let down, equiv. to kathe- (var. s. of kathiénai, equiv. to kat- CATA- + hiénai to send, let go) + -tér agent suffix ]