Webster's Unabridged Dictionary - Letter H - Page 58
Hydrofluate (n.) (Chem.) A supposed compound of hydrofluoris acid and a base; a fluoride. [Archaic.]
Hydrofluoric (a.) (Chem.) Pertaining to, or containing, hydrogen and fluorine; fluohydric; as, hydrofluoric acid.
Hydrofluoric acid (Chem.), A colorless, mobile, volatile liquid, HF, very corrosive in its action, and having a strong, pungent, suffocating odor. It is produced by the action of sulphuric acid on fluorite, and is usually collected as a solution in water. It attacks all silicates, as glass or porcelain, is the agent employed in etching glass, and is preserved only in vessels of platinum, lead, caoutchouc, or gutta-percha.
Hydrofluosilicate (n.) (Chem.) A salt of hydrofluosilic acid; a silicofluoride. See Silicofluoride.
Hydrofluosilicic (a.) (Chem.) Pertaining to, or denoting, a compound consisting of a double fluoride of hydrogen and silicon; silicofluoric. See Silicofluoric.
Hydrofluosilicic acid (n.) (Chemistry) 氟矽酸 A compound consisting of a double fluoride of hydrogen and silicon; silicofluoric acid.
Compare: Fluosilicic
Fluosilicic (a.) (Chem.) Composed of, or derived from, silicon and fluorine.
Fluosilicic acid, () A double fluoride of hydrogen and silicon, H2F6Si, obtained in solution in water as a sour fuming liquid, and regarded as the type of the fluosilicates; -- called also silicofluoric acid, and hydrofluosilicic acid.
Hydrofluosilicic acid (n.) An unstable poisonous corrosive acid known primarily in the form of its salts [syn: fluosilicic acid, hydrofluosilicic acid].
Hydrogalvanic (a.) Pertaining to, produced by, or consisting of, electricity evolved by the action or use of fluids; as, hydrogalvanic currents. [R.]
Hydrogen (n.) (Chem.) 氫 A gaseous element, colorless, tasteless, and odorless, the lightest known substance, being fourteen and a half times lighter than air (hence its use in filling balloons), and over eleven thousand times lighter than water. It is very abundant, being an ingredient of water and of many other substances, especially those of animal or vegetable origin. It may by produced in many ways, but is chiefly obtained by the action of acids (as sulphuric) on metals, as zinc, iron, etc. It is very inflammable, and is an ingredient of coal gas and water gas. It is standard of chemical equivalents or combining weights, and also of valence, being the typical monad. Symbol H. Atomic weight 1.
Note: Although a gas, hydrogen is chemically similar to the metals in its nature, having the properties of a weak base. It is, in all acids, the base which is replaced by metals and basic radicals to form salts. Like all other gases, it is condensed by great cold and pressure to a liquid which freezes and solidifies by its own evaporation. It is absorbed in large quantities by certain metals (esp. palladium), forming alloy-like compounds; hence, in view of quasi-metallic nature, it is sometimes called hydrogenium. It is the typical reducing agent, as opposed to oxidizers, as oxygen, chlorine, etc.
Bicarbureted hydrogen, An old name for ethylene.
Carbureted hydrogen gas. See under Carbureted.
Hydrogen dioxide, A thick, colorless liquid, H2O2, resembling water, but having a bitter, sour taste, produced by the action of acids on barium peroxide. It decomposes into water and oxygen, and is manufactured in large quantities for an oxidizing and bleaching agent. Called also oxygenated water.
Hydrogen oxide, A chemical name for water, H?O.
Hydrogen sulphide, A colorless inflammable gas, H2S, having the characteristic odor of bad eggs, and found in many mineral springs. It is produced by the action of acids on metallic sulphides, and is an important chemical reagent. Called also sulphureted hydrogen.
Hydrogen (n.) A nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe [syn: {hydrogen}, {H}, {atomic number 1}].
Hydrogen
Symbol: H
Atomic number: 1
Atomic weight: 1.0079
Colourless, odourless gaseous chemical element. Lightest and most abundant element in the universe. Present in water and in all organic compounds. Chemically reacts with most elements. Discovered by Henry Cavendish in 1776.
Hydrogen (n.) [ U ] (Symbol H) 氫，氫氣 A chemical element that is the lightest gas, has no colour, taste, or smell, and combines with oxygen to form water.
Hydrogenated (imp. & p. p.) of Hydrogenate
Hydrogenating (p. pr. & vb. n.) of Hydrogenate
Hydrogenate (v. t.) (Chem.) To hydrogenize.
Hydrogenate (v.) Combine or treat with or expose to hydrogen; add hydrogen to the molecule of (an unsaturated organic compound) [ant: dehydrogenate].
Hydrogenation (n.) (Chem.) The act of combining with hydrogen, or the state of being so combined.
Hydrogenation (n.) A chemical process that adds hydrogen atoms to an unsaturated oil; "food producers use hydrogenation to keep fat from becoming rancid".
Hydrogenide (n.) (Chem.) A binary compound containing hydrogen; a hydride. [R.] See Hydride.
Hydrogenium (n.) (Chem.) Hydrogen; -- called also in view of its supposed metallic nature. -- Graham.
Hydrogenized (imp. & p. p.) of Hydrogenize
Hydrogenizing (p. pr. & vb. n.) of Hydrogenize
Hydrogenize (v. t.) (Chem.) To combine with hydrogen; to treat with, or subject to the action of, hydrogen; to reduce; -- contrasted with oxidize.
Hydrogenous (a.) Of or pertaining to hydrogen; containing hydrogen.
Hydrognosy (n.) A treatise upon, or a history and description of, the water of the earth.
Hydrogode (n.) (Elec.) The negative pole or cathode. [Obs & R.]
Hydrographer (n.) One skilled in the hydrography; one who surveys, or draws maps or charts of, the sea, lakes, or other waters, with the adjacent shores; one who describes the sea or other waters.
Hydrographic (a.) Alt. of Hydrographical
Hydrographical (a.) Of or relating to hydrography.
Hydrographic (a.) Of or relating to the science of hydrography [syn: hydrographic, hydrographical].
Hydrography (n.) The art of measuring and describing the sea, lakes, rivers, and other waters, with their phenomena.
Hydrography (n.) That branch of surveying which embraces the determination of the contour of the bottom of a harbor or other sheet of water, the depth of soundings, the position of channels and shoals, with the construction of charts exhibiting these particulars.
Hydrography (n.) The science of the measurement and description and mapping of the surface waters of the earth with special reference to navigation.
Hydroguret (n.) (Chem.) A hydride. [Obs.]
Hydroid (a.) (Zool.) Related to, or resembling, the hydra; of or pertaining to the Hydroidea.
Hydroid (n.) One of the Hydroideas.
Hydroid (n.) Colonial coelenterates having the polyp phase dominant [syn: hydrozoan, hydroid].
Hydroidea (n. pl.) (Zool.) An extensive order of Hydrozoa or Acalephae. [Written also Hydroida.]
Note: This order includes the hydras and the free-swimming hydromedus[ae], together with a great variety of marine attached hydroids, many of which grow up into large, elegantly branched forms, consisting of a vast number of zooids (hydranths, gonophores, etc.), united by hollow stems. All the zooids of a colony are produced from one primary zooid, by successive buddings. The Siphonophora have also been included in this order by some writers. See Gymnoblastea, Hydromedusa, Gonosome, Gonotheca.
Hydrokinetic (a.) Of or pertaining to the motions of fluids, or the forces which produce or affect such motions; -- opposed to hydrostatic. -- Sir W. Thomson.
Hydrokinetic (a.) Relating to fluids in motion or the forces that produce or affect such motion [ant: hydrostatic].
Hydrological (a.) Of or pertaining to hydrology.
Hydrologist (n.) One skilled in hydrology.
Hydrologist (n.) A geologist skilled in hydrology.
Hydrology (n.) The science of water, its properties, phenomena, and distribution over the earth's surface.
Hydrology (n.) The branch of geology that studies water on the earth and in the atmosphere: its distribution and uses and conservation.
Hydrolytic (a.) (Chem.) Tending to remove or separate water; eliminating water. [Archaic]
Hydrolytic (a.) (Chem.) Of, pertaining to, or accompanied by hydrolysis.
Hydrolytic agents, Such as sulphuric acid or caustic alkali. -- Encyc. Brit.
Hydrolytic ferment (Physiol. Chem.), An enzyme (formerly referred to as a ferment), which acts only in the presence of water, and which causes the substance acted upon to take up a molecule of water, resulting in the splitting of a chemical bond and often splitting one compound into two. Thus, diastase of malt, ptyalin of saliva, and boiling dilute sulphuric acid all convert starch by hydration into dextrin and sugar. Nearly all of the digestive enzymes are hydrolytic in their action. Since 1910 such an enzyme is {hydrolase">usually referred to as a {hydrolase or {hydrolytic enzyme}.
Hydromagnesite (n.) (Min.) A hydrous carbonate of magnesia occurring in white, early, amorphous masses.
Hydromancy (n.) Divination by means of water, -- practiced by the ancients.
Hydromancy (n.) Divination by water (as by patterns seen in the ebb and flow of the tides).
Hydromantic (a.) Of or pertaining to divination by water.
Hydromechanics (n.) That branch of physics which treats of the mechanics of liquids, or of their laws of equilibrium and of motion.
Hydromedusae (n. pl. ) of Hydromedusa
Hydromedusa (n.) (Zool.) Any medusa or jellyfish which is produced by budding from a hydroid. They are called also Craspedota, and naked-eyed medusae.
Note: Such medus[ae] are the reproductive zooids or gonophores, either male or female, of the hydroid from which they arise, whether they become free or remain attached to the hydroid colony. They in turn produce the eggs from which the hydroids are developed. The name is also applied to other similar medus[ae] which are not known to bud from a hydroid colony, and even to some which are known to develop directly from the eggs, but which in structure agree essentially with those produced from hydroids. See Hydroidea, and Gymnoblastea.
Hydromel (n.) A liquor consisting of honey diluted in water, and after fermentation called mead.
Hydromellonic (a.) See Cyamellone.
Hydrometallurgical (a.) Of or pertaining to hydrometallurgy; involving the use of liquid reagents in the treatment or reduction of ores. -- Hy`dro*met`al*lur"gic*al*ly, adv.
Hydrometallurgy (n.) The art or process of assaying or reducing ores by means of liquid reagents.
Hydrometeor (n.) A meteor or atmospheric phenomenon dependent upon the vapor of water; -- in the pl., a general term for the whole aqueous phenomena of the atmosphere, as rain, snow, hail, etc. -- Nichol.
Hydrometeorological (a.) Of or pertaining to hydrometeorology, or to rain, clouds, storms, etc.
Hydrometeorology (n.) That branch of meteorology which relates to, or treats of, water in the atmosphere, or its phenomena, as rain, clouds, snow, hail, storms, etc.
Hydrometer (n.) (Physics) An instrument for determining the specific gravities of liquids, and thence the strength spirituous liquors, saline solutions, etc.
Note: It is usually made of glass with a graduated stem, and indicates the specific gravity of a liquid by the depth to which it sinks in it, the zero of the scale marking the depth to which it sinks in pure water. Extra weights are sometimes used to adapt the scale to liquids of different densities.
Hydrometer (n.) An instrument, variously constructed, used for measuring the velocity or discharge of water, as in rivers, from reservoirs, etc., and called by various specific names according to its construction or use, as tachometer, rheometer, hydrometer, pendulum, etc.; a current gauge. Hydrometric
Hydrometer (n.) A measuring instrument for determining the specific gravity of a liquid or solid [syn: hydrometer, gravimeter].
Hydrometer () An instrument for measuring the density of fluids; being immersed in fluids, as in water, brine, beer, brandy, &c., it determines the proportion of their densities, or their specific gravities, and thence their qualities.
Hydrometer () By, the Act of Congress of January 12, 1825, 3 Story's' Laws U. S. 1976, the secretary of the treasury is authorized, under the direction of the president of the United States, to adopt and substitute such hydrometer as he may deem best calculated to promote the public interest, in lieu of that now prescribed by law, for the purpose of ascertaining the proof of liquors; and that after such adoption and substitution, the duties imposed by law upon distilled spirits shall be levied, collected and paid, according to the proof ascertained by any hydrometer so substituted and adopted.
Hydrometric (a.) Alt. of Hydrometrical
Hydrometrical (a.) Of or pertaining to an hydrometer, or to the determination of the specific gravity of fluids.
Hydrometrical (a.) Of or pertaining to measurement of the velocity, discharge, etc., of running water.
Hydrometrical (a.) Made by means of an hydrometer; as, hydrometric observations.
Hydrometric pendulum, A species of hydrometer consisting of a hollow ball of ivory or metal suspended by a treated from the center of a graduated quadrant, and held in a stream to measure the velocity of the water by the inclination given to the thread; a kind of current gauge.
Hydrometric (a.) Of or relating to hydrometry [syn: hydrometric, gravimetric].
Hydrometrograph (n.) An instrument for determining and recording the quantity of water discharged from a pipe, orifice, etc., in a given time.
Hydrometry (n.) The art of determining the specific gravity of liquids, and thence the strength of spirituous liquors, saline solutions, etc.
Hydrometry (n.) The art or operation of measuring the velocity or discharge of running water, as in rivers, etc.
Hydrometry (n.) The measurement of specific gravity [syn: hydrometry, gravimetry].
Hydromica (n.) (Min.) A variety of potash mica containing water. It is less elastic than ordinary muscovite.
Hydromica schist (Min.), A mica schist characterized by the presence of hydromica. It often has a silky luster and almost soapy feel.
Compare: Mica
Mica (n.) (Min.) The name of a group of minerals characterized by highly perfect cleavage, so that they readily separate into very thin leaves, more or less elastic. They differ widely in composition, and vary in color from pale brown or yellow to green or black. The transparent forms are used in lanterns, the doors of stoves, etc., being popularly called isinglass. Formerly called also cat-silver, and glimmer.
Note: The important species of the mica group are: muscovite, common or potash mica, pale brown or green, often silvery, including damourite (also called hydromica and muscovy glass); biotite, iron-magnesia mica, dark brown, green, or black; lepidomelane, iron, mica, black; phlogopite, magnesia mica, colorless, yellow, brown; lepidolite, lithia mica, rose-red, lilac.
Mica (usually muscovite, also biotite) Is an essential constituent of granite, gneiss, and mica slate; biotite is common in many eruptive rocks; phlogopite in crystalline limestone and serpentine.
Mica diorite (Min.), An eruptive rock allied to diorite but containing mica (biotite) instead of hornblende.
Mica powder, A kind of dynamite containing fine scales of mica.
Mica schist, Mica slate (Geol.), A schistose rock, consisting of mica and quartz with, usually, som feldspar.
Hydronephrosis (n.) (Med.) An accumulation of urine in the pelvis of the kidney, occasioned by obstruction in the urinary passages.
Hydronephrosis (n.) Accumulation of urine in the kidney because of an obstruction in the ureter.
Hydropath (n.) A hydropathist. Hydropathic
Hydropathic (a.) Alt. of Hydropathical
Hydropathical (a.) Of or pertaining to hydropathy.
Hydropathic (a.) Of or relating to hydropathy or its administration; "hydropathic treatments".
Hydropathist (n.) One who practices hydropathy; a water-cure doctor.
Hydropathy (n.) The water cure; a mode of treating diseases by the copious and frequent use of pure water, both internally and externally.
Hydroperitoneum (n.) Same as Ascites.
Hydrophane (n.) A semitranslucent variety of opal that becomes translucent or transparent on immersion in water.
Hydrophanous (a.) Made transparent by immersion in water.
Hydrophid (n.) Any sea snake of the genus Hydrophys and allied genera. These snakes are venomous, live upon fishes, and have a flattened tail for swimming.
Hydrophlorone (n.) A white, crystalline benzene derivative, C8H10O2, obtained by the reduction of phlorone.
Hydrophobia (n.) An abnormal dread of water, said to be a symptom of canine madness; hence:
Hydrophobia (n.) The disease caused by a bite form, or inoculation with the saliva of, a rabid creature, of which the chief symptoms are, a sense of dryness and construction in the throat, causing difficulty in deglutition, and a marked heightening of reflex excitability, producing convulsions whenever the patient attempts to swallow, or is disturbed in any way, as by the sight or sound of water; rabies; canine madness.
Hydrophobic (a.) Of or pertaining to hydrophobia; producing or caused by rabies; as, hydrophobic symptoms; the hydrophobic poison.
Hydrophoby (n.) See Hydrophobia.
Hydrophone (n.) 水聽器；水管測漏器；【醫】水診器 A microphone which detects sound waves under water.
Hydrophora (n. pl.) The Hydroidea.
Hydrophore (n.) An instrument used for the purpose of obtaining specimens of water from any desired depth, as in a river, a lake, or the ocean.
Hydrophyllia (n. pl. ) of Hydrophyllium
Hydrophylliums (n. pl. ) of Hydrophyllium
Hydrophyllium (n.) One of the flat, leaflike, protective zooids, covering other zooids of certain Siphonophora.
Hydrophyte (n.) An aquatic plant; an alga.
Hydrophytology (n.) The branch of botany which treats of water plants.
Hydropic (a.) Alt. of Hydropical
Hydropical (a.) Dropsical, or resembling dropsy.
Hydropically (adv.) In a hydropical manner.
Hydropiper (n.) A species (Polygonum Hydropiper) of knotweed with acrid foliage; water pepper; smartweed.
Hydropneumatic (a.) Pertaining to, or depending upon, both liquid and gaseous substances; as, hydropneumatic apparatus for collecting gases over water or other liquids.
Hydropsy (n.) Same as Dropsy.
Hydropult (n.) A machine for throwing water by hand power, as a garden engine, a fire extinguisher, etc.
Hydroquinone (n.) A white crystalline substance, C6H4(OH)2, obtained by the reduction of quinone. It is a diacid phenol, resembling, and metameric with, pyrocatechin and resorcin. Called also dihydroxy benzene.
Hydrorhizae (n. pl. ) of Hydrorhiza
Hydrorhizas (n. pl. ) of Hydrorhiza
Hydrorhiza (n.) The rootstock or decumbent stem by which a hydroid is attached to other objects. See Illust. under Hydroidea.
Hydrosalt (n.) A salt supposed to be formed by a hydracid and a base.
Hydrosalt (n.) An acid salt.
Hydrosalt (n.) A hydrous salt; a salt combined with water of hydration or crystallization.
Hydroscope (n.) An instrument designed to mark the presence of water, especially in air.
Hydroscope (n.) A kind of water clock, used anciently for measuring time, the water tricking from an orifice at the end of a graduated tube.
Hydrosome (n.) Alt. of Hydrosoma
Hydrosoma (n.) All the zooids of a hydroid colony collectively, including the nutritive and reproductive zooids, and often other kinds.
Hydrosorbic (a.) Pertaining to, or designating, an acid obtained from sorbic acid when this takes up hydrogen; as, hydrosorbic acid.
Hydrostat (n.) A contrivance or apparatus to prevent the explosion of steam boilers.
Hydrostatic (a.) Alt. of Hydrostatical
Hydrostatical (a.) Of or relating to hydrostatics; pertaining to, or in accordance with, the principles of the equilibrium of fluids.
Hydrostatically (adv.) According to hydrostatics, or to hydrostatic principles.