(organic chemistry) A compound consisting only of carbon and hydrogen atoms.

(physics) Of, or relating to the science of hydrodynamics. / Operated by the force of water in motion.

The science of the properties, distribution, and effects of water on a planet's surface, in the soil and underlying rocks, and in the atmosphere

(chemistry) Of or relating to hydrochloric acid.

(chemistry) A univalent radical or functional group (–OH) in organic chemistry; present in alcohols, phenols, carboxylic acids and certain other classes of compounds.

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

(transitive) To take up, consume or become linked to water. / (slang) To drink water. / (programming) To load data from a database record into an object's variables

A thermonuclear bomb that derives its destructive power from the fusion of isotopes of hydrogen (deuterium and tritium).

(firefighting) A device used by firefighters to obtain water from the main supply, consisting of a barrel, connections for hose and a valve assembly.

(chemistry) An univalent anion (OH⁻) based on the hydroxyl functional group. / Any substance containing such an anion.