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.

(Greek mythology) A mythological serpent with many heads, slain by Hercules as one of his twelve labours.

plural of hydra

plural of hydra

a solitary polyp about 10 mm long, usually found attached to the under surfaces of water plants in ponds and streams. Similar to a sea anemone consisting of a hollow cylinder with a mouth surrounded by tentacles.

plural of freshwater hydra

Pertaining to water. / Related to, or operated by, hydraulics.

(transitive) To mine using the technique of hydraulic mining.

The engineering science that deals with practical applications where liquid is in motion and transmits energy. / The hydraulic system of a vehicle or other machine.

(chemistry) A solid compound containing or linked to water molecules. / (inorganic chemistry, rare) Water.