Definition of "hydra" in Anglais

noun

1. (fantasy) A dragon-like creature with many heads and the ability to regrow them when maimed.

2. (biology) Any of several small freshwater polyps of the genus Hydra and related genera, having a naked cylindrical body and an oral opening surrounded by tentacles.

3. (figurative) A complex, multifarious problem or situation that cannot be easily and rapidly solved.