What is the meaning of Hydra?

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

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.

A complex, multifarious problem or situation that cannot be easily and rapidly solved.

Hydra, a mythological serpent with seven heads

something monstrous which is extremely difficult to fight with (often connected with organized crime)

Hydra, a genus of hydrozoan in family Hydridae

A water-snake.

hydra (any freshwater polyp of the genus Hydra)

hydra (dragon-like creature with many heads and the ability to regrow them when maimed)

evil that is difficult to eradicate

Source: wiktionary.org