Gordius \Gor"di*us\, n. [NL. See {Gordian}, 1.] (Zool.)
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.
[1913 Webster]