<B>hydrogenase, </B>noun.<DL COMPACT><DD> an enzyme found in various bacteria that can move molecular hydrogen in and out of organic compounds. </DL>
<A NAME="hydrogenate">
<B>hydrogenate, </B>transitive verb, <B>-ated,</B> <B>-ating.</B><DL COMPACT><DD> to combinewith hydrogen; treat with hydrogen. When vegetable oils are hydrogenated, they become solid fats. noun <B>hydrogenation.</B> </DL>
<A NAME="hydrogenator">
<B>hydrogenator, </B>noun.<DL COMPACT><DD> a device used to combine or treat substances with hydrogen. <BR> <I>Ex. The hydrogenator carries out the necessary adjustment of the hydrogen carbon ratio ... by adding hydrogen to the fuel (London Times).</I> </DL>
<A NAME="hydrogenbomb">
<B>hydrogen bomb,</B><DL COMPACT><DD> a bomb that uses the fusion of atoms to cause an explosion of tremendous force; fusion bomb; superatomic bomb. It is many times more powerful than the atomic bomb. <BR> <I>Ex. On Mar. 1, 1954 the United States exploded a hydrogen bomb estimated in strength at between 15 and 17 megatons--or the equivalent of 15 to 17 million tons of TNT (Newsweek).</I> <DL COMPACT><DD> Also, <B>H-bomb.</B> </DL>
</DL>
<A NAME="hydrogenbond">
<B>hydrogen bond,</B><DL COMPACT><DD> a chemical bond in which the hydrogen atom of one molecule is attracted to the electronegative atom of another molecule, as in compounds containing nitrogen, oxygen, or fluorine. <BR> <I>Ex. Hydrogen bonds hold life's molecules in shape, and play a vital role in enzyme catalysis, the action of drugs and anaesthetics, and taste (New Scientist).</I> </DL>
<A NAME="hydrogencyanide">
<B>hydrogen cyanide,</B> =hydrocyanic acid.</DL>
<A NAME="hydrogendioxide">
<B>hydrogen dioxide,</B> =hydrogen peroxide.</DL>
<A NAME="hydrogenfluoride">
<B>hydrogen fluoride,</B><DL COMPACT><DD> a colorless, corrosive, poisonous gas which can cause severe burns. </DL>
<A NAME="hydrogenion">
<B>hydrogen ion,</B><DL COMPACT><DD> a positively charged ion of hydrogen found in all acids in the hydrated form. </DL>
<B>hydrogenolysis, </B>noun, pl. <B>-ses.</B><DL COMPACT><DD> chemical decomposition in which a compound is broken down and changed into other compounds by interaction with hydrogen. </DL>
<A NAME="hydrogenous">
<B>hydrogenous, </B>adjective.<DL COMPACT><DD> of or containing hydrogen. </DL>
<A NAME="hydrogenperoxide">
<B>hydrogen peroxide,</B><DL COMPACT><DD> a colorless liquid compound of hydrogen and oxygen; hydrogen dioxide; peroxide. It is used in water solution as an antiseptic, to bleach hair, and as a rocket propellant. </DL>
<A NAME="hydrogensulfide">
<B>hydrogen sulfide,</B><DL COMPACT><DD> an inflammable, poisonous gas with an odor like that of rotten eggs, often found in mineral waters. </DL>
<A NAME="hydrogeological">
<B>hydrogeological, </B>adjective.<DL COMPACT><DD> of or having to do with hydrogeology. </DL>
<A NAME="hydrogeology">
<B>hydrogeology, </B>noun.<DL COMPACT><DD> a branch of geology that deals with surface and subterranean water, its geographical distribution, and the ways in which it affects the features and composition of the earth's crust. noun <B>hydrogeologist.</B> </DL>
<A NAME="hydrograph">
<B>hydrograph, </B>noun.<DL COMPACT><DD> a hydrographic record, diagram, or chart. </DL>
<A NAME="hydrographer">
<B>hydrographer, </B>noun.<DL COMPACT><DD> a person skilled in hydrography. </DL>
<A NAME="hydrographic">
<B>hydrographic, </B>adjective.<DL COMPACT><DD> of or having to do with hydrography. <BR> <I>Ex. a hydrographic survey.</I> adv. <B>hydrographically.</B> </DL>
<A NAME="hydrography">
<B>hydrography, </B>noun.<DL COMPACT><DD> the science of measuring, describing, and charting seas, lakes, rivers, and other bodies of water, with special reference to their use for navigation and commerce. </DL>
<A NAME="hydroid">
<B>hydroid, </B>noun, adjective.<DL COMPACT><DD><I>noun </I> <B>1. </B>the polyp form of a coelenterate as distinguished from a jellyfish. Hydroids grow in branching colonies by budding. <DD><B> 2. </B>any sessile hydrozoan. <DD><I>adj. </I> of or like the hydrozoans. </DL>
<A NAME="hydrokinetic">
<B>hydrokinetic, </B>adjective.<DL COMPACT><DD> having to do with the motion of fluids, or with hydrokinetics. </DL>
<A NAME="hydrokinetics">
<B>hydrokinetics, </B>noun.<DL COMPACT><DD> the kinetics of fluids; branch of physics dealing with the motion of fluids. See also <B>hydraulics.</B> </DL>
<A NAME="hydrolase">
<B>hydrolase, </B>noun.<DL COMPACT><DD> an enzyme that catalyzes the removal of water from a substrate. </DL>
<A NAME="hydrolite">
<B>hydrolite, </B>noun.<DL COMPACT><DD> a type of red geode found in Uruguay that contains quartz crystals left when water that once contained silica evaporated; water stone. </DL>
<A NAME="hydrologic">
<B>hydrologic, </B>adjective.<DL COMPACT><DD> of or having to do with hydrology. adv. <B>hydrologically.</B> </DL>
<A NAME="hydrological">
<B>hydrological, </B>adjective. =hydrologic.</DL>
<A NAME="hydrologiccycle">
<B>hydrologic cycle,</B> =water cycle.</DL>
<A NAME="hydrology">
<B>hydrology, </B>noun.<DL COMPACT><DD> the science that deals with water, with special reference to its properties, laws, and geographical distribution. noun <B>hydrologist.</B> </DL>
<B>hydrolysis, </B>noun, pl. <B>-ses.</B><DL COMPACT><DD> a chemical process in which a compound is broken down and changed into other compounds by taking up the elements of water. </DL>
<A NAME="hydrolyte">
<B>hydrolyte, </B>noun.<DL COMPACT><DD> a compound that undergoes hydrolysis. </DL>
<A NAME="hydrolytic">
<B>hydrolytic, </B>adjective.<DL COMPACT><DD> of or producing hydrolysis. adv. <B>hydrolytically.</B> </DL>
<A NAME="hydrolyzate">
<B>hydrolyzate, </B>noun.<DL COMPACT><DD> a product of hydrolysis. </DL>
<A NAME="hydrolyze">
<B>hydrolyze, </B>transitive verb, intransitive verb, <B>-lyzed,</B> <B>-lyzing.</B><DL COMPACT><DD> to decompose by hydrolysis. <BR> <I>Ex. When a peptide or protein is hydrolyzed ... it breaks down into amino acids (Scientific American).</I> adj. <B>hydrolyzable.</B> noun <B>hydrolyzation.</B> </DL>
<A NAME="hydromagnetic">
<B>hydromagnetic, </B>adjective.<DL COMPACT><DD> of or having to do with hydromagnetics. adv. <B>hydromagnetically.</B> </DL>
<A NAME="hydromagnetics">
<B>hydromagnetics, </B>noun.<DL COMPACT><DD> a branch of physics that deals with the principles of hydrodynamics applied to electrically conducting fluids, such as plasma, and that studies the relationship of such fluids with a magnetic field. </DL>
<A NAME="hydromancy">
<B>hydromancy, </B>noun.<DL COMPACT><DD> divination by means of water. noun <B>hydromancer.</B> </DL>
<A NAME="hydromantic">
<B>hydromantic, </B>adjective.<DL COMPACT><DD> of or having to do with hydromancy. </DL>
<A NAME="hydromechanical">
<B>hydromechanical, </B>adjective.<DL COMPACT><DD><B> 1. </B>of or having to do with hydromechanics. <DD><B> 2. </B>of or having to do with the use of water in mechanical devices. </DL>
<A NAME="hydromechanics">
<B>hydromechanics, </B>noun.<DL COMPACT><DD> the science of the mechanics of fluids or of their laws of equilibrium and motion. </DL>
<A NAME="hydromedusa">
<B>hydromedusa, </B>noun, pl. <B>-sae.</B><DL COMPACT><DD> a free-swimming jellyfish produced asexually by a hydroid. </DL>
<A NAME="hydromedusan">
<B>hydromedusan, </B>adjective, noun.<DL COMPACT><DD><I>adj. </I> of or having to do with the hydromedusae. <DD><I>noun </I> <B>=hydromedusa.</B> </DL>
<A NAME="hydromel">
<B>hydromel, </B>noun.<DL COMPACT><DD> a liquor consisting of honey and water. Hydromel when fermented is called mead. </DL>
<A NAME="hydrometallurgical">
<B>hydrometallurgical, </B>adjective.<DL COMPACT><DD> of or having to do with hydrometallurgy. </DL>
<A NAME="hydrometallurgy">
<B>hydrometallurgy, </B>noun.<DL COMPACT><DD> the treatment of minerals and ores by wet processes, especially the dissolving of metals in aqueous solutions of acids, bases, or salts, and related operations in connection with extracting the metals. </DL>
<A NAME="hydrometeor">
<B>hydrometeor, </B>noun.<DL COMPACT><DD> a meteorological phenomenon involving the vapor of water, as rain, snow, or hail. </DL>
<A NAME="hydrometeorological">
<B>hydrometeorological, </B>adjective.<DL COMPACT><DD> of or having to do with hydrometeorology. </DL>
<A NAME="hydrometeorology">
<B>hydrometeorology, </B>noun.<DL COMPACT><DD> the branch of meteorology dealing with atmospheric phenomena depending on water vapor. noun <B>hydrometeorologist.</B> </DL>
<A NAME="hydrometer">
<B>hydrometer, </B>noun.<DL COMPACT><DD> a graduated instrument for finding the specific gravity of liquids. A hydrometer is used to test the battery of an automobile. The amount that the weighted inner glass tube sinks in the liquid indicates the concentration of acid in the battery. </DL>
<A NAME="hydrometric">
<B>hydrometric, </B>adjective.<DL COMPACT><DD> of or having to do with hydrometry or a hydrometer. </DL>
<B>hydrometry, </B>noun.<DL COMPACT><DD> the determination of specific gravity by means of a hydrometer. </DL>
<A NAME="hydronaut">
<B>hydronaut, </B>noun.<DL COMPACT><DD> a member of the United States Navy trained to work in undersea vessels engaged in search and rescue missions and in research projects. </DL>
<A NAME="hydronic">
<B>hydronic, </B>adjective.<DL COMPACT><DD> of or having to do with hydronics. <BR> <I>Ex. hydronic heating.</I> </DL>
<A NAME="hydronics">
<B>hydronics, </B>noun pl.<DL COMPACT><DD> the methods or operations involved in the cooling or heating by electrically regulated circulation of fluids. </DL>
<A NAME="hydronium">
<B>hydronium, </B>noun.<DL COMPACT><DD> a hydrogen ion combined with a molecule of water. </DL>
<A NAME="hydropath">
<B>hydropath, </B>noun. =hydropathist.</DL>
<A NAME="hydropathic">
<B>hydropathic, </B>adjective, noun.<DL COMPACT><DD><I>adj. </I> of or using hydropathy. <DD><I>noun </I> a sanitarium that specializes in hydropathy. </DL>
<A NAME="hydropathist">
<B>hydropathist, </B>noun.<DL COMPACT><DD> a person who practices or favors hydropathy. </DL>
<A NAME="hydropathy">
<B>hydropathy, </B>noun.<DL COMPACT><DD> the treatment of disease by using quantities of water externally and internally; water cure. </DL>
<A NAME="hydroperoxide">
<B>hydroperoxide, </B>noun.<DL COMPACT><DD> any one of a class of compounds containing the group OOH-. Hydrogen peroxide is the simplest hydroperoxide. </DL>
