Fistula \Fis"tu*la\ (?; 135), n.; pl. Fistul[ae]. [L.]

1. A reed; a pipe.

2. A pipe for convejing water. [Obs.]

--Knight.

3. (Med.) A permanent abnormal opening into the soft parts with a constant discharge; a deep, narrow, chronic abscess; an abnormal opening between an internal cavity and another cavity or the surface; as, a salivary fistula; an anal fistula; a recto-vaginal fistula.

Incomplete fistula (Med.), a fistula open at one end only.

Source: Webster's Revised Unabridged Dictionary (1913)