gordius

from The Century Dictionary.

• noun The typical genus of threadworms of the family Gordiidæ; the hair-worms or hair-eels.
• noun [lowercase; pl. gordii (-ī).] A species or an individual of the genus Gordius; a gordian.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) A genus of long, slender, nematoid worms, parasitic in insects until near maturity, when they leave the insect, and live in water, in which they deposit their eggs; -- called also hair eel, hairworm, and hair snake, from the absurd, but common and widely diffused, notion that they are metamorphosed horsehairs.

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

• noun legendary king of ancient Phrygia who was said to be responsible for the Gordian knot