FIS'TULA, noun [Latin ; Eng. whistle.] 1. Properly, a pipe; a wind instrument of music, originally a reed. 2. A surgery, a deep, narrow and callous ulcer, generally arising from abscesses. It differs from a sinus, in being callous. Fistula lachrymalis, a fistula of the lachrymal sac, a disorder accompanied with a flowing of tears.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI