\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.