Catheter, Foley: A flexible plastic tube (a catheter) inserted into the bladder to provide continuous urinary drainage.
The "Foley" has a balloon on the bladder end. After the catheter is inserted in the bladder, the balloon is inflated (with air or fluid) so that the catheter cannot pull out but is retained in the bladder as an "indwelling" catheter. Removal is accomplished simply by deflating the balloon and slipping the catheter out.
The "Foley" is named for the American urologist Frederic Eugene Basil Foley (1891-1966).