Definition of Catheter

Catheter: A thin, flexible tube. For example, a catheter placed in a vein provides a pathway for giving drugs, nutrients, fluids, or blood products. Samples of blood can also be withdrawn through the catheter.

The catheter was created by the Greeks. "Katheter" originally referred to an instrument that was inserted such as a plug. The word "katheter" in turn came from "kathiemai" meaning "to sound" with a probe. The ancient Greeks inserted a hollow metal tube through the urethra into the bladder to empty it and the tube came to be known as a "katheter."

For specific information about a particular type of catheters or catheterization, please see:
Central venous catheter
Foley catheter
Indwelling bladder catheter
Swan-Ganz catheter and
Venous catheterization.