fistula

from The American Heritage® Dictionary of the English Language, 4th Edition

• n. An abnormal duct or passage resulting from injury, disease, or a congenital disorder that connects an abscess, cavity, or hollow organ to the body surface or to another hollow organ.

from Wiktionary, Creative Commons Attribution/Share-Alike License

• n. An abnormal connection or passageway between organs or vessels that normally do not connect.
• n. A tube, a pipe, or a hole.

from the GNU version of the Collaborative International Dictionary of English

• n. A reed; a pipe.
• n. A pipe for convejing water.
• n. 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

from The Century Dictionary and Cyclopedia

• n. A reed; a pipe; a wind-instrument of music.
• n. In the Roman Catholic Church, same as calamus, 4.
• n. In pathology, a narrow passage or duct, formed by disease or injury, leading from an abscess to a free surface, or furnishing an abnormal means of egress from some normal cavity, as in vesicovaginal fistula.
• n. [capitalized] [NL.] In zoology, a genus of polyps.
• n. A tube or pipe which normally connects some internal part or organ of an animal with the surrounding air or water, as the trachea of an insect or the blow-hole of a whale.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• n. an abnormal passage leading from a suppurating cavity to the body surface
• n. a chronic inflammation of the withers of a horse