gordius

Century Dictionary and Cyclopedia

1. n. The typical genus of threadworms of the family Gordiidæ; the hair-worms or hair-eels. A common species is called G. aquaticus. These creatures are so slender that they are popularly supposed to be animated horse-hairs, or to be produced from hose-hairs which fall into the water.
2. n. [lowercase; pl. gordii (-ī).] A species or an individual of the genus Gordius; a gordian.

GNU Webster's 1913

1. n. (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.

WordNet 3.0

1. n. legendary king of ancient Phrygia who was said to be responsible for the Gordian knot