Hydra

Part of speech: noun

Pronunciation: /ˈhaɪdɹə/

Definitions

1. A mythical serpent with many heads that regrow when cut off ; a simple freshwater animal with radial symmetry and tentacles used to catch prey
2. A legendary creature known for its regenerative multiple heads ; a small aquatic invertebrate living in freshwater often studied for its regenerative abilities
3. An ancient monster symbolized by multiple regrowing heads ; a tiny freshwater animal characterized by a tubular body and stinging cells for feeding

Etymology: The Hydra was a serpentine monster of Greek myth, slain by Heracles as one of his labours at Lerna. Its defining trick was regeneration: every time Heracles cut off a head, two new ones grew in its place. Heracles eventually solved the problem with help from his nephew Iolaus, who cauterised each neck with fire as the head fell, so that no new heads could sprout. The word's later uses grew out of that legend. Biologists named a small freshwater animal "hydra" because its body can bud off new individuals, much as the monster grew new heads, and the same image of endless regrowth gave the word a figurative sense: a problem that cannot be dispatched by one decisive blow. That figurative sense is a contrast with the Gordian knot, the tangle that Alexander the Great cut through with a single stroke of his sword.

Synonyms: monster, serpent