Dictionary.net

• One that will hold itself within the bladder.

1898 - American pocket medical dictionary
By Willam Alexander Newman Dorland

• A urethral catheter which from some peculiarity of its curve or by reason of being furnished with elastic winglike processes, will remain in the bladder without the use of any supplementary appliance.

1916 - Appleton's medical dictionary
By Smith Ely Jelliffe