hydro-, hydra-, hydr-, hyd-

(Greek: water)

A thermostat for regulating the temperature of water.
Hydrotherapy in which heated water is utilized as a treatment for physical ailments.
A “fisher lizard” from Late Cretaceous North America. Its name comes from Greek hydrotheras, “fisherman”. It was found in the Maastrichtian Moreno Formation, Panoche Hills, Fresno County, California. Named by U. S. paleontologist Samuel Paul Welles in 1943.
An apparatus for testing the hardness of water.
1. Measuring the hardness of water.
2. Determining the concentration of cations; such as, calcium and magnesium in water.
A procedure in which tissues are separated or dissected free by injecting water or other fluid under high pressure.
hydrotribophile (s) (noun), hydrotribophiles (pl)
Plants and animals that thrive in badlands [an arid or semi-arid area with scanty vegetation and marked surface erosion; or an area of barren land having roughly eroded ridges, peaks, and mesas].
hydrotribophyte (s) (noun), hydrotribophytes (pl)
A badlands plant.
hydrotrope, hydrotropic
A compound that increases the aqueous solubility of various slightly soluble organic compounds.
hydrotropism (s) (noun)
The growth or directional response or turning of an organism toward or away from water or moisture.
1. The tendency of a substance only slightly soluble in water, to dissolve readily in other aqueous solutions.
2. The orientation response to water; such as, the tendency of an organism to orientate itself towards water or away for water.
3. The deviation response of parts of plants (especially, roots) towards moisture.
A methyl with hydroxide replacing the hydrogen atoms.
Hydrozoa (pl) (noun)
A class of coelenterates, Cœlenterata: The Hydrozoa make up one of two main subdivisions of the subkingdom, Actinozoa, and include various simple and compound polyps and jellyfishes having no "stomodeum" or gastric tentacles.
hydrozoan (s) (noun), hydrozoans (pl)
Any freshwater or marine coelenterate of the class Hydrozoa: The hydrozoans include the free-swimming or attached types, as the hydra, in which one developmental stage, either the polyp or medusa, is absent, and colonial types, as the Portuguese man-of-war, in which both medusa and polyp stages are present in a single colony.
magnetohydrodynamics, magnetohydrodynamic; MHD
1. The study of the interaction of magnetic fields and electrically conducting liquids or gases; such as, molten metal or plasma.
2. A theoretical procedure that would drive warships and submarines in seawater by having the water enter a cylindrical duct running through the hull and the interaction between a vertical magnetic field and an electric current passing horizontally through the water in the duct which pushes the water out of the stern, generating thrust.

Cross references of word families that refer to "water": aqua-; hydat-; hygro-.